{
    "document": {
        "category": "csaf_base",
        "csaf_version": "2.0",
        "distribution": {
            "tlp": {
                "label": "WHITE"
            }
        },
        "lang": "en",
        "notes": [
            {
                "category": "legal_disclaimer",
                "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
            }
        ],
        "publisher": {
            "category": "coordinator",
            "contact_details": "cert@ncsc.nl",
            "name": "National Cyber Security Centre",
            "namespace": "https://www.ncsc.nl/"
        },
        "title": "CVE-2026-23943",
        "tracking": {
            "current_release_date": "2026-03-20T09:53:48.636257Z",
            "generator": {
                "date": "2026-02-17T15:00:00Z",
                "engine": {
                    "name": "V.E.L.M.A",
                    "version": "1.7"
                }
            },
            "id": "CVE-2026-23943",
            "initial_release_date": "2026-03-13T02:41:52.253786Z",
            "revision_history": [
                {
                    "date": "2026-03-13T02:41:52.253786Z",
                    "number": "1",
                    "summary": "CVE created.| Source connected.| CVE status created. (valid)"
                },
                {
                    "date": "2026-03-13T02:41:55.484592Z",
                    "number": "2",
                    "summary": "NCSC Score created."
                },
                {
                    "date": "2026-03-13T09:38:50.770897Z",
                    "number": "3",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (4).| Product Identifiers created (4).| References created (5).| CWES updated (1)."
                },
                {
                    "date": "2026-03-13T09:38:53.970557Z",
                    "number": "4",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-13T11:35:06.188556Z",
                    "number": "5",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-13T12:05:39.839578Z",
                    "number": "6",
                    "summary": "Source connected.| CVE status created. (valid)| Products connected (9).| References created (6)."
                },
                {
                    "date": "2026-03-13T12:05:47.020159Z",
                    "number": "7",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-13T14:25:22.428828Z",
                    "number": "8",
                    "summary": "Source created.| CVE status created. (valid)| EPSS created."
                },
                {
                    "date": "2026-03-13T14:25:29.629850Z",
                    "number": "9",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-13T16:39:25.495552Z",
                    "number": "10",
                    "summary": "Unknown change."
                },
                {
                    "date": "2026-03-13T20:30:11.625166Z",
                    "number": "11",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (5).| CWES updated (1)."
                },
                {
                    "date": "2026-03-13T20:30:19.389137Z",
                    "number": "12",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-15T18:42:57.697622Z",
                    "number": "13",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| Products connected (2)."
                },
                {
                    "date": "2026-03-15T18:42:59.872912Z",
                    "number": "14",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-17T12:19:51.899874Z",
                    "number": "15",
                    "summary": "Source connected.| CVE status created. (valid)| Description created for source.| Products connected (2).| CWES updated (1)."
                },
                {
                    "date": "2026-03-17T12:19:54.948624Z",
                    "number": "16",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-19T12:19:55.326250Z",
                    "number": "17",
                    "summary": "Product Remediations created (2)."
                },
                {
                    "date": "2026-03-19T12:20:06.809116Z",
                    "number": "18",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-20T09:53:44.144238Z",
                    "number": "19",
                    "summary": "Source connected.| CVE status created. (valid)| EPSS created."
                },
                {
                    "date": "2026-03-20T09:53:47.505922Z",
                    "number": "20",
                    "summary": "NCSC Score updated."
                }
            ],
            "status": "interim",
            "version": "20"
        }
    },
    "product_tree": {
        "branches": [
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<26.2.5.18",
                                "product": {
                                    "name": "vers:unknown/<26.2.5.18",
                                    "product_id": "CSAFPID-5813188"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<27.3.4.9",
                                "product": {
                                    "name": "vers:unknown/<27.3.4.9",
                                    "product_id": "CSAFPID-5813187"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<28.4.1",
                                "product": {
                                    "name": "vers:unknown/<28.4.1",
                                    "product_id": "CSAFPID-5813189"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<5.1.4.14",
                                "product": {
                                    "name": "vers:unknown/<5.1.4.14",
                                    "product_id": "CSAFPID-5813185"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<5.2.11.6",
                                "product": {
                                    "name": "vers:unknown/<5.2.11.6",
                                    "product_id": "CSAFPID-5813184"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<5.5.1",
                                "product": {
                                    "name": "vers:unknown/<5.5.1",
                                    "product_id": "CSAFPID-5813186"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<9.1.0.5",
                                "product": {
                                    "name": "vers:unknown/<9.1.0.5",
                                    "product_id": "CSAFPID-5813183"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<9.3.2.3",
                                "product": {
                                    "name": "vers:unknown/<9.3.2.3",
                                    "product_id": "CSAFPID-5813191"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<9.6.1",
                                "product": {
                                    "name": "vers:unknown/<9.6.1",
                                    "product_id": "CSAFPID-5813190"
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "Erlang/OTP"
                    }
                ],
                "category": "vendor",
                "name": "Open Source"
            },
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:git/07b8f441ca711f9812fad9e9115bab3c3aa92f79|<*",
                                "product": {
                                    "name": "vers:git/07b8f441ca711f9812fad9e9115bab3c3aa92f79|<*",
                                    "product_id": "CSAFPID-2918861",
                                    "product_identification_helper": {
                                        "cpe": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:otp/17.0|<*",
                                "product": {
                                    "name": "vers:otp/17.0|<*",
                                    "product_id": "CSAFPID-2918860",
                                    "product_identification_helper": {
                                        "cpe": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:otp/3.0.1|<*",
                                "product": {
                                    "name": "vers:otp/3.0.1|<*",
                                    "product_id": "CSAFPID-5812823",
                                    "product_identification_helper": {
                                        "cpe": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:purl/pkg:otp/ssh@3.0.1|<pkg:otp/ssh@*",
                                "product": {
                                    "name": "vers:purl/pkg:otp/ssh@3.0.1|<pkg:otp/ssh@*",
                                    "product_id": "CSAFPID-3108477",
                                    "product_identification_helper": {
                                        "cpe": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
                                    }
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "OTP"
                    }
                ],
                "category": "vendor",
                "name": "Erlang"
            },
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:microsoft/*",
                                        "product": {
                                            "name": "vers:microsoft/*",
                                            "product_id": "CSAFPID-5775805",
                                            "product_identification_helper": {
                                                "cpe": "cpe:2.3:a:microsoft:azl3_erlang_26.2.5.17-1:*:*:*:*:*:*:*:*"
                                            }
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "azl3 erlang 26.2.5.17-1 on Azure Linux 3.0"
                            },
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:microsoft/*",
                                        "product": {
                                            "name": "vers:microsoft/*",
                                            "product_id": "CSAFPID-5197860",
                                            "product_identification_helper": {
                                                "cpe": "cpe:2.3:a:microsoft:cbl2_erlang_25.3.2.21-4:*:*:*:*:*:*:*:*"
                                            }
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "cbl2 erlang 25.3.2.21-4 on CBL Mariner 2.0"
                            }
                        ],
                        "category": "product_family",
                        "name": "Open Source Software"
                    }
                ],
                "category": "vendor",
                "name": "Microsoft"
            },
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:deb/unknown",
                                        "product": {
                                            "name": "vers:deb/unknown",
                                            "product_id": "CSAFPID-2209294"
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "erlang"
                            }
                        ],
                        "category": "product_family",
                        "name": "bookworm"
                    },
                    {
                        "branches": [
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:deb/unknown",
                                        "product": {
                                            "name": "vers:deb/unknown",
                                            "product_id": "CSAFPID-2209295"
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "erlang"
                            }
                        ],
                        "category": "product_family",
                        "name": "bullseye"
                    }
                ],
                "category": "vendor",
                "name": "Debian"
            }
        ]
    },
    "vulnerabilities": [
        {
            "cve": "CVE-2026-23943",
            "cwe": {
                "id": "CWE-409",
                "name": "Improper Handling of Highly Compressed Data (Data Amplification)"
            },
            "notes": [
                {
                    "category": "description",
                    "text": "Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Resource Depletion.\n\nThe SSH transport layer advertises legacy zlib compression by default and inflates attacker-controlled payloads pre-authentication without any size limit, enabling reliable memory exhaustion DoS.\n\nTwo compression algorithms are affected:\n\n* zlib: Activates immediately after key exchange, enabling unauthenticated attacks\n* zlib@openssh.com: Activates post-authentication, enabling authenticated attacks\n\nEach SSH packet can decompress ~255 MB from 256 KB of wire data (1029:1 amplification ratio). Multiple packets can rapidly exhaust available memory, causing OOM kills in memory-constrained environments.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_transport.erl and program routines ssh_transport:decompress/2, ssh_transport:handle_packet_part/4.\n\nThis issue affects OTP from OTP 17.0 until OTP 28.4.1, 27.3.4.9 and 26.2.5.18 corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.",
                    "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-23943"
                },
                {
                    "category": "description",
                    "text": "Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Resource Depletion.\n\nThe SSH transport layer advertises legacy zlib compression by default and inflates attacker-controlled payloads pre-authentication without any size limit, enabling reliable memory exhaustion DoS.\n\nTwo compression algorithms are affected:\n\n* zlib: Activates immediately after key exchange, enabling unauthenticated attacks\n* zlib@openssh.com: Activates post-authentication, enabling authenticated attacks\n\nEach SSH packet can decompress ~255 MB from 256 KB of wire data (1029:1 amplification ratio). Multiple packets can rapidly exhaust available memory, causing OOM kills in memory-constrained environments.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_transport.erl and program routines ssh_transport:decompress/2, ssh_transport:handle_packet_part/4.\n\nThis issue affects OTP from OTP 17.0 until OTP 28.4.1, 27.3.4.9 and 26.2.5.18 corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.",
                    "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-23943"
                },
                {
                    "category": "description",
                    "text": "Improper Handling of Highly Compressed Data (Compression Bomb) vulnerability in Erlang OTP ssh (ssh_transport modules) allows Denial of Service via Resource Depletion.  The SSH transport layer advertises legacy zlib compression by default and inflates attacker-controlled payloads pre-authentication without any size limit, enabling reliable memory exhaustion DoS.  Two compression algorithms are affected:  * zlib: Activates immediately after key exchange, enabling unauthenticated attacks * zlib@openssh.com: Activates post-authentication, enabling authenticated attacks  Each SSH packet can decompress ~255 MB from 256 KB of wire data (1029:1 amplification ratio). Multiple packets can rapidly exhaust available memory, causing OOM kills in memory-constrained environments.  This vulnerability is associated with program files lib/ssh/src/ssh_transport.erl and program routines ssh_transport:decompress/2, ssh_transport:handle_packet_part/4.  This issue affects OTP from OTP 17.0 until OTP 28.4.1, 27.3.4.9 and 26.2.5.18 corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.",
                    "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-23943"
                },
                {
                    "category": "description",
                    "text": "Pre-auth SSH DoS via unbounded zlib inflate",
                    "title": "microsoft - https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Mar"
                },
                {
                    "category": "other",
                    "text": "0.00041",
                    "title": "EPSS"
                },
                {
                    "category": "other",
                    "text": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
                    "title": "CVSSV4"
                },
                {
                    "category": "other",
                    "text": "6.9",
                    "title": "CVSSV4 base score"
                },
                {
                    "category": "other",
                    "text": "5.0",
                    "title": "NCSC Score"
                },
                {
                    "category": "other",
                    "text": "VENDOR FIX as product remediation category, There is product data available from source Certbundde, The value of the most recent CVSS (V4) score",
                    "title": "NCSC Score top increasing factors"
                },
                {
                    "category": "other",
                    "text": "The value of the most recent CVSS (V3) score, There is product data available from source Debian",
                    "title": "NCSC Score top decreasing factors"
                }
            ],
            "product_status": {
                "known_affected": [
                    "CSAFPID-2918860",
                    "CSAFPID-2918861",
                    "CSAFPID-3108477",
                    "CSAFPID-5812823",
                    "CSAFPID-5813183",
                    "CSAFPID-5813184",
                    "CSAFPID-5813185",
                    "CSAFPID-5813186",
                    "CSAFPID-5813187",
                    "CSAFPID-5813188",
                    "CSAFPID-5813189",
                    "CSAFPID-5813190",
                    "CSAFPID-5813191",
                    "CSAFPID-2209294",
                    "CSAFPID-2209295",
                    "CSAFPID-5197860",
                    "CSAFPID-5775805"
                ]
            },
            "references": [
                {
                    "category": "external",
                    "summary": "Source - hkcert",
                    "url": "https://www.hkcert.org/security-bulletin/erlang-otp-multiple-vulnerabilities_20260313"
                },
                {
                    "category": "external",
                    "summary": "Source - cveprojectv5",
                    "url": "https://www.cve.org/CVERecord?id=CVE-2026-23943"
                },
                {
                    "category": "external",
                    "summary": "Source raw - cveprojectv5",
                    "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/23xxx/CVE-2026-23943.json"
                },
                {
                    "category": "external",
                    "summary": "Source - certbundde",
                    "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0721.json"
                },
                {
                    "category": "external",
                    "summary": "Source - first",
                    "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-23943"
                },
                {
                    "category": "external",
                    "summary": "Source raw - first",
                    "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
                },
                {
                    "category": "external",
                    "summary": "Source - nvd",
                    "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23943"
                },
                {
                    "category": "external",
                    "summary": "Source raw - nvd",
                    "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-23943"
                },
                {
                    "category": "external",
                    "summary": "Source - debian",
                    "url": "https://security-tracker.debian.org/tracker/CVE-2026-23943"
                },
                {
                    "category": "external",
                    "summary": "Source - microsoft",
                    "url": "https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Mar"
                },
                {
                    "category": "external",
                    "summary": "Source - first",
                    "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde; cveprojectv5; nvd",
                    "url": "https://github.com/erlang/otp/security/advisories/GHSA-c836-qprm-jw9r"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://github.com/erlang/otp/commit/43a87b949bdff12d629a8c34146711d9da93b1b1"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://github.com/erlang/otp/commit/93073c3bd338c60cd2bae715ce6a1d4ffc1a8fd3"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; nvd",
                    "url": "https://github.com/erlang/otp/commit/0c1c04b191f6ab940e8fcfabce39eb5a8a6440a4"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde",
                    "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0721.json"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde",
                    "url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-0721"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde",
                    "url": "https://github.com/erlang/otp/releases/tag/OTP-27.3.4.9"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde",
                    "url": "https://github.com/erlang/otp/releases/tag/OTP-28.4.1"
                },
                {
                    "category": "external",
                    "summary": "Reference - certbundde",
                    "url": "https://github.com/erlang/otp/security/advisories/GHSA-4749-w85x-hw9h"
                }
            ],
            "remediations": [
                {
                    "category": "vendor_fix",
                    "details": "CBL-Mariner Releases",
                    "product_ids": [
                        "CSAFPID-5197860",
                        "CSAFPID-5775805"
                    ]
                }
            ],
            "title": "CVE-2026-23943"
        }
    ]
}