{
    "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-2026-27641",
        "tracking": {
            "current_release_date": "2026-03-23T03:40:00.825133Z",
            "generator": {
                "date": "2026-02-17T15:00:00Z",
                "engine": {
                    "name": "V.E.L.M.A",
                    "version": "1.7"
                }
            },
            "id": "CVE-2026-27641",
            "initial_release_date": "2026-02-25T04:24:53.835089Z",
            "revision_history": [
                {
                    "date": "2026-02-25T04:24:53.835089Z",
                    "number": "1",
                    "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)."
                },
                {
                    "date": "2026-02-25T04:25:03.295761Z",
                    "number": "2",
                    "summary": "NCSC Score created."
                },
                {
                    "date": "2026-02-25T04:38:42.497233Z",
                    "number": "3",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (3).| CWES updated (1)."
                },
                {
                    "date": "2026-02-25T04:38:45.224295Z",
                    "number": "4",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-02-25T15:13:44.256304Z",
                    "number": "5",
                    "summary": "Source created.| CVE status created. (valid)| EPSS created."
                },
                {
                    "date": "2026-02-25T15:13:46.516219Z",
                    "number": "6",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-02-25T19:39:51.629036Z",
                    "number": "7",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (5).| CWES updated (1)."
                },
                {
                    "date": "2026-02-25T21:39:05.853925Z",
                    "number": "8",
                    "summary": "Unknown change."
                },
                {
                    "date": "2026-02-26T00:38:44.276571Z",
                    "number": "9",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (11).| Product Identifiers created (10).| References created (4).| CWES updated (1)."
                },
                {
                    "date": "2026-02-26T12:53:16.490697Z",
                    "number": "10",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (5).| CWES updated (1)."
                },
                {
                    "date": "2026-02-27T19:25:41.586480Z",
                    "number": "11",
                    "summary": "Products connected (1).| Product Identifiers created (1).| Exploits created (1).| CWES updated (1)."
                },
                {
                    "date": "2026-02-27T19:25:43.461365Z",
                    "number": "12",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-02-27T22:39:44.006365Z",
                    "number": "13",
                    "summary": "CWES updated (1)."
                },
                {
                    "date": "2026-02-28T07:17:46.932838Z",
                    "number": "14",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-02-28T12:35:34.156410Z",
                    "number": "15",
                    "summary": "CWES updated (1)."
                },
                {
                    "date": "2026-03-02T15:58:57.010898Z",
                    "number": "16",
                    "summary": "Source created.| CVE status created. (valid)| Description created for source.| Products created (1)."
                },
                {
                    "date": "2026-03-02T15:59:06.853558Z",
                    "number": "17",
                    "summary": "NCSC Score updated."
                },
                {
                    "date": "2026-03-20T09:40:21.967064Z",
                    "number": "18",
                    "summary": "Source connected.| CVE status created. (valid)| EPSS created."
                },
                {
                    "date": "2026-03-20T09:40:25.053067Z",
                    "number": "19",
                    "summary": "NCSC Score updated."
                }
            ],
            "status": "interim",
            "version": "19"
        }
    },
    "product_tree": {
        "branches": [
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.2.0",
                                "product": {
                                    "name": "vers:unknown/0.2.0",
                                    "product_id": "CSAFPID-5729952"
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.3",
                                "product": {
                                    "name": "vers:unknown/0.3",
                                    "product_id": "CSAFPID-5723125",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@0.3"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.3.1",
                                "product": {
                                    "name": "vers:unknown/0.3.1",
                                    "product_id": "CSAFPID-5723126",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@0.3.1"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.3.2",
                                "product": {
                                    "name": "vers:unknown/0.3.2",
                                    "product_id": "CSAFPID-5723127",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@0.3.2"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.4.0",
                                "product": {
                                    "name": "vers:unknown/0.4.0",
                                    "product_id": "CSAFPID-5723128",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@0.4.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/0.5.0",
                                "product": {
                                    "name": "vers:unknown/0.5.0",
                                    "product_id": "CSAFPID-5723129",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@0.5.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/1.0.0",
                                "product": {
                                    "name": "vers:unknown/1.0.0",
                                    "product_id": "CSAFPID-5723130",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@1.0.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/1.1.0",
                                "product": {
                                    "name": "vers:unknown/1.1.0",
                                    "product_id": "CSAFPID-5723131",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@1.1.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/1.2.0",
                                "product": {
                                    "name": "vers:unknown/1.2.0",
                                    "product_id": "CSAFPID-5723132",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@1.2.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/1.3.0",
                                "product": {
                                    "name": "vers:unknown/1.3.0",
                                    "product_id": "CSAFPID-5723133",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@1.3.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/1.4.0",
                                "product": {
                                    "name": "vers:unknown/1.4.0",
                                    "product_id": "CSAFPID-5723134",
                                    "product_identification_helper": {
                                        "purl": "pkg:pypi/flask-reuploaded@1.4.0"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<1.5.0",
                                "product": {
                                    "name": "vers:unknown/<1.5.0",
                                    "product_id": "CSAFPID-5700891",
                                    "product_identification_helper": {
                                        "cpe": "cpe:2.3:a:jugmac00:flask-reuploaded:*:*:*:*:*:python:*:*"
                                    }
                                }
                            },
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/>=0|<1.5.0",
                                "product": {
                                    "name": "vers:unknown/>=0|<1.5.0",
                                    "product_id": "CSAFPID-5723135"
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "flask-reuploaded"
                    }
                ],
                "category": "vendor",
                "name": "jugmac00"
            },
            {
                "branches": [
                    {
                        "branches": [
                            {
                                "category": "product_version_range",
                                "name": "vers:unknown/<1.5.0",
                                "product": {
                                    "name": "vers:unknown/<1.5.0",
                                    "product_id": "CSAFPID-5753612"
                                }
                            }
                        ],
                        "category": "product_name",
                        "name": "flask-reuploaded"
                    }
                ],
                "category": "vendor",
                "name": "unknown"
            }
        ]
    },
    "vulnerabilities": [
        {
            "cve": "CVE-2026-27641",
            "cwe": {
                "id": "CWE-1336",
                "name": "Improper Neutralization of Special Elements Used in a Template Engine"
            },
            "notes": [
                {
                    "category": "description",
                    "text": "Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.",
                    "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-27641"
                },
                {
                    "category": "description",
                    "text": "Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.",
                    "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-27641"
                },
                {
                    "category": "description",
                    "text": "### Impact\nA critical path traversal and extension bypass vulnerability in Flask-Reuploaded allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI).\n\n### Patches\nFlask-Reuploaded has been patched in version 1.5.0\n\n### Workarounds\n\n1. **Do not pass user input to the `name` parameter**\n2. Use auto-generated filenames only\n3. Implement strict input validation if `name` must be used\n\n```python\nfrom werkzeug.utils import secure_filename\nimport os\n\n# Sanitize user input before passing to save()\nsafe_name = secure_filename(request.form.get('custom_name'))\n# Remove path separators\nsafe_name = os.path.basename(safe_name)\n# Validate extension matches policy\nif not photos.extension_allowed(photos.get_extension(safe_name)):\n    abort(400)\n    \nfilename = photos.save(file, name=safe_name)\n```\n\n### Resources\nThe fix is documented in the pull request, see https://github.com/jugmac00/flask-reuploaded/pull/180.\n\nA proper write-up was created by the reporter of the vulnerability, Jaron Cabral (https://www.linkedin.com/in/jaron-cabral-751994357/), but is not yet available as of time of this publication.",
                    "title": "github - https://github.com/advisories/GHSA-65mp-fq8v-56jr"
                },
                {
                    "category": "description",
                    "text": "### Impact\nA critical path traversal and extension bypass vulnerability in Flask-Reuploaded allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI).\n\n### Patches\nFlask-Reuploaded has been patched in version 1.5.0\n\n### Workarounds\n\n1. **Do not pass user input to the `name` parameter**\n2. Use auto-generated filenames only\n3. Implement strict input validation if `name` must be used\n\n```python\nfrom werkzeug.utils import secure_filename\nimport os\n\n# Sanitize user input before passing to save()\nsafe_name = secure_filename(request.form.get('custom_name'))\n# Remove path separators\nsafe_name = os.path.basename(safe_name)\n# Validate extension matches policy\nif not photos.extension_allowed(photos.get_extension(safe_name)):\n    abort(400)\n    \nfilename = photos.save(file, name=safe_name)\n```\n\n### Resources\nThe fix is documented in the pull request, see https://github.com/jugmac00/flask-reuploaded/pull/180.\n\nA proper write-up was created by the reporter of the vulnerability, Jaron Cabral (https://www.linkedin.com/in/jaron-cabral-751994357/), but is not yet available as of time of this publication.",
                    "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/PyPI%2FGHSA-65mp-fq8v-56jr.json?alt=media"
                },
                {
                    "category": "description",
                    "text": "Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.",
                    "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-27641.json?alt=media"
                },
                {
                    "category": "description",
                    "text": "Affected versions of the flask-reuploaded package are vulnerable to Remote Code Execution due to improper sanitization of a user-controlled upload filename that enables path traversal and extension bypass. The vulnerability occurs when photos.save(file, name=...) accepts attacker-supplied values in the name parameter, allowing crafted path separators and mismatched extensions to bypass photos.get_extension() and photos.extension_allowed() checks and writes attacker-controlled template content to an unintended location where it can later be processed by a template engine (SSTI).",
                    "title": "pyupio - https://pyupio.github.io/safety-db/#flask-reuploaded"
                },
                {
                    "category": "other",
                    "text": "0.00128",
                    "title": "EPSS"
                },
                {
                    "category": "other",
                    "text": "4.0",
                    "title": "NCSC Score"
                },
                {
                    "category": "other",
                    "text": "There is cvss data available from a private source, There is product data available from a private source",
                    "title": "NCSC Score top increasing factors"
                },
                {
                    "category": "other",
                    "text": "Is related to a product by vendor Unknown, There is exploit data available from source Nvd, Exploit code publicly available",
                    "title": "NCSC Score top decreasing factors"
                }
            ],
            "product_status": {
                "known_affected": [
                    "CSAFPID-5700891",
                    "CSAFPID-5723125",
                    "CSAFPID-5723126",
                    "CSAFPID-5723127",
                    "CSAFPID-5723128",
                    "CSAFPID-5723129",
                    "CSAFPID-5723130",
                    "CSAFPID-5723131",
                    "CSAFPID-5723132",
                    "CSAFPID-5723133",
                    "CSAFPID-5723134",
                    "CSAFPID-5723135",
                    "CSAFPID-5729952",
                    "CSAFPID-5753612"
                ]
            },
            "references": [
                {
                    "category": "external",
                    "summary": "Source - nvd",
                    "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27641"
                },
                {
                    "category": "external",
                    "summary": "Source raw - nvd",
                    "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-27641"
                },
                {
                    "category": "external",
                    "summary": "Source - cveprojectv5",
                    "url": "https://www.cve.org/CVERecord?id=CVE-2026-27641"
                },
                {
                    "category": "external",
                    "summary": "Source raw - cveprojectv5",
                    "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/27xxx/CVE-2026-27641.json"
                },
                {
                    "category": "external",
                    "summary": "Source - first",
                    "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-27641"
                },
                {
                    "category": "external",
                    "summary": "Source raw - first",
                    "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
                },
                {
                    "category": "external",
                    "summary": "Source - github",
                    "url": "https://github.com/advisories/GHSA-65mp-fq8v-56jr"
                },
                {
                    "category": "external",
                    "summary": "Source raw - github",
                    "url": "https://api.github.com/advisories/GHSA-65mp-fq8v-56jr"
                },
                {
                    "category": "external",
                    "summary": "Source - osv",
                    "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/PyPI%2FGHSA-65mp-fq8v-56jr.json?alt=media"
                },
                {
                    "category": "external",
                    "summary": "Source - osv",
                    "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-27641.json?alt=media"
                },
                {
                    "category": "external",
                    "summary": "Source - pyupio",
                    "url": "https://pyupio.github.io/safety-db/#flask-reuploaded"
                },
                {
                    "category": "external",
                    "summary": "Source raw - pyupio",
                    "url": "https://raw.githubusercontent.com/pyupio/safety-db/refs/heads/master/data/insecure_full.json"
                },
                {
                    "category": "external",
                    "summary": "Source - first",
                    "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; github; nvd; osv",
                    "url": "https://github.com/jugmac00/flask-reuploaded/commit/d64c6b2f71cb73734fc38baa0e3e156926361288"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; github; nvd; osv",
                    "url": "https://github.com/jugmac00/flask-reuploaded/pull/180"
                },
                {
                    "category": "external",
                    "summary": "Reference - cveprojectv5; github; nvd; osv",
                    "url": "https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-65mp-fq8v-56jr"
                },
                {
                    "category": "external",
                    "summary": "Reference - github; osv",
                    "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27641"
                },
                {
                    "category": "external",
                    "summary": "Reference - github",
                    "url": "https://github.com/advisories/GHSA-65mp-fq8v-56jr"
                },
                {
                    "category": "external",
                    "summary": "Reference - osv",
                    "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27641.json"
                }
            ],
            "scores": [
                {
                    "cvss_v3": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                        "baseScore": 9.8,
                        "baseSeverity": "CRITICAL"
                    },
                    "products": [
                        "CSAFPID-5700891",
                        "CSAFPID-5723125",
                        "CSAFPID-5723126",
                        "CSAFPID-5723127",
                        "CSAFPID-5723128",
                        "CSAFPID-5723129",
                        "CSAFPID-5723130",
                        "CSAFPID-5723131",
                        "CSAFPID-5723132",
                        "CSAFPID-5723133",
                        "CSAFPID-5723134",
                        "CSAFPID-5723135",
                        "CSAFPID-5729952",
                        "CSAFPID-5753612"
                    ]
                }
            ],
            "title": "CVE-2026-27641"
        }
    ]
}