{
    "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-2026-34763",
        "tracking": {
            "current_release_date": "2026-04-03T15:36:51.876359Z",
            "generator": {
                "date": "2026-02-17T15:00:00Z",
                "engine": {
                    "name": "V.E.L.M.A",
                    "version": "1.7"
                }
            },
            "id": "CVE-2026-34763",
            "initial_release_date": "2026-04-02T17:28:26.822985Z",
            "revision_history": [
                {
                    "date": "2026-04-02T17:28:26.822985Z",
                    "number": "1",
                    "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)."
                },
                {
                    "date": "2026-04-02T17:28:29.558712Z",
                    "number": "2",
                    "summary": "NCSC Score created."
                },
                {
                    "date": "2026-04-02T17:39:35.282657Z",
                    "number": "3",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (3).| References created (1).| CWES updated (1)."
                },
                {
                    "date": "2026-04-02T17:39:36.867632Z",
                    "number": "4",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-04-02T18:47:59.637243Z",
                    "number": "5",
                    "summary": "Unknown change."
                },
                {
                    "date": "2026-04-02T20:52:57.756093Z",
                    "number": "6",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)."
                },
                {
                    "date": "2026-04-02T20:53:02.103467Z",
                    "number": "7",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-04-03T00:44:16.485715Z",
                    "number": "8",
                    "summary": "Source created.| CVE status created. (valid)| Products connected (2)."
                },
                {
                    "date": "2026-04-03T00:44:18.158899Z",
                    "number": "9",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-04-03T06:45:59.984673Z",
                    "number": "10",
                    "summary": "Description created for source."
                },
                {
                    "date": "2026-04-03T15:30:59.817886Z",
                    "number": "11",
                    "summary": "Source connected.| CVE status created. (valid)| EPSS created."
                },
                {
                    "date": "2026-04-03T15:31:04.965492Z",
                    "number": "12",
                    "summary": "NCSC Score updated."
                }
            ],
            "status": "interim",
            "version": "12"
        }
    },
    "product_tree": {
        "branches": [
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<2.2.23",
                                "product": {
                                    "name": "vers:unknown/<2.2.23",
                                    "product_id": "CSAFPID-5985093"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/>=3.0.0.beta1|<3.1.21",
                                "product": {
                                    "name": "vers:unknown/>=3.0.0.beta1|<3.1.21",
                                    "product_id": "CSAFPID-5985094"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/>=3.2.0|<3.2.6",
                                "product": {
                                    "name": "vers:unknown/>=3.2.0|<3.2.6",
                                    "product_id": "CSAFPID-5985095"
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "rack"
                    }
                ],
                "category": "vendor",
                "name": "rack"
            },
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:deb/unknown",
                                        "product": {
                                            "name": "vers:deb/unknown",
                                            "product_id": "CSAFPID-2065710"
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "ruby-rack"
                            }
                        ],
                        "category": "product_family",
                        "name": "bookworm"
                    },
                    {
                        "branches": [
                            {
                                "branches": [
                                    {
                                        "category": "product_version_range",
                                        "name": "vers:deb/unknown",
                                        "product": {
                                            "name": "vers:deb/unknown",
                                            "product_id": "CSAFPID-2065711"
                                        }
                                    }
                                ],
                                "category": "product_name",
                                "name": "ruby-rack"
                            }
                        ],
                        "category": "product_family",
                        "name": "bullseye"
                    }
                ],
                "category": "vendor",
                "name": "Debian"
            }
        ]
    },
    "vulnerabilities": [
        {
            "cve": "CVE-2026-34763",
            "cwe": {
                "id": "CWE-625",
                "name": "Permissive Regular Expression"
            },
            "notes": [
                {
                    "category": "description",
                    "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.",
                    "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34763"
                },
                {
                    "category": "description",
                    "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.",
                    "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34763.json"
                },
                {
                    "category": "description",
                    "text": "## Summary\n\n`Rack::Directory` interpolates the configured `root` path directly into a regular expression when deriving the displayed directory path. If `root` contains regex metacharacters such as `+`, `*`, or `.`, the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output.\n\n## Details\n\n`Rack::Directory::DirectoryBody#each` computes the visible path using code equivalent to:\n\n```ruby\nshow_path = Utils.escape_html(path.sub(/\\A#{root}/, ''))\n```\n\nHere, `root` is a developer-configured filesystem path. It is normalized earlier with `File.expand_path(root)` and then inserted directly into a regular expression without escaping.\n\nBecause the value is treated as regex syntax rather than as a literal string, metacharacters in the configured path can change how the prefix match behaves. When that happens, the expected root prefix is not removed from `path`, and the absolute filesystem path is rendered into the HTML directory listing.\n\n## Impact\n\nIf `Rack::Directory` is configured to serve a directory whose absolute path contains regex metacharacters, the generated directory listing may disclose the full server filesystem path instead of only the request-relative path.\n\nThis can expose internal deployment details such as directory layout, usernames, mount points, or naming conventions that would otherwise not be visible to clients.\n\n## Mitigation\n\n* Update to a patched version of Rack in which the root prefix is removed using an escaped regular expression.\n* Avoid using `Rack::Directory` with a root path that contains regular expression metacharacters.",
                    "title": "github - https://api.github.com/advisories/GHSA-7mqq-6cf9-v2qp"
                },
                {
                    "category": "description",
                    "text": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.",
                    "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-34763"
                },
                {
                    "category": "other",
                    "text": "0.00028",
                    "title": "EPSS"
                },
                {
                    "category": "other",
                    "text": "4.2",
                    "title": "NCSC Score"
                },
                {
                    "category": "other",
                    "text": "The value of the most recent EPSS score, Is related to (a version of) an uncommon product",
                    "title": "NCSC Score top decreasing factors"
                }
            ],
            "product_status": {
                "known_affected": [
                    "CSAFPID-5985093",
                    "CSAFPID-5985094",
                    "CSAFPID-5985095",
                    "CSAFPID-2065710",
                    "CSAFPID-2065711"
                ]
            },
            "references": [
                {
                    "category": "external",
                    "summary": "Source - nvd",
                    "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34763"
                },
                {
                    "category": "external",
                    "summary": "Source - cveprojectv5",
                    "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34763.json"
                },
                {
                    "category": "external",
                    "summary": "Source - github",
                    "url": "https://api.github.com/advisories/GHSA-7mqq-6cf9-v2qp"
                },
                {
                    "category": "external",
                    "summary": "Source - debian",
                    "url": "https://security-tracker.debian.org/tracker/CVE-2026-34763"
                },
                {
                    "category": "external",
                    "summary": "Source - first",
                    "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; github; nvd",
                    "url": "https://github.com/rack/rack/security/advisories/GHSA-7mqq-6cf9-v2qp"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34763"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/advisories/GHSA-7mqq-6cf9-v2qp"
                }
            ],
            "scores": [
                {
                    "cvss_v3": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM"
                    },
                    "products": [
                        "CSAFPID-2065710",
                        "CSAFPID-2065711",
                        "CSAFPID-5985093",
                        "CSAFPID-5985094",
                        "CSAFPID-5985095"
                    ]
                }
            ],
            "title": "CVE-2026-34763"
        }
    ]
}