PYSEC-2026-2320

Vulnerability from pysec - Published: 2026-02-21 06:17 - Updated: 2026-07-13 05:52
VLAI
Details

Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safe_join accepts paths with multiple segments, such as example/NUL. The function send_from_directory uses safe_join to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Impacted products
Name purl
werkzeug pkg:pypi/werkzeug
Aliases
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "werkzeug",
        "purl": "pkg:pypi/werkzeug"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1",
        "0.10",
        "0.10.1",
        "0.10.2",
        "0.10.3",
        "0.10.4",
        "0.11",
        "0.11.1",
        "0.11.10",
        "0.11.11",
        "0.11.12",
        "0.11.13",
        "0.11.14",
        "0.11.15",
        "0.11.2",
        "0.11.3",
        "0.11.4",
        "0.11.5",
        "0.11.6",
        "0.11.7",
        "0.11.8",
        "0.11.9",
        "0.12",
        "0.12.1",
        "0.12.2",
        "0.13",
        "0.14",
        "0.14.1",
        "0.15.0",
        "0.15.1",
        "0.15.2",
        "0.15.3",
        "0.15.4",
        "0.15.5",
        "0.15.6",
        "0.16.0",
        "0.16.1",
        "0.2",
        "0.3",
        "0.3.1",
        "0.4",
        "0.4.1",
        "0.5",
        "0.5.1",
        "0.6",
        "0.6.1",
        "0.6.2",
        "0.7",
        "0.7.1",
        "0.7.2",
        "0.8",
        "0.8.1",
        "0.8.2",
        "0.8.3",
        "0.9",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6",
        "1.0.0",
        "1.0.0rc1",
        "1.0.1",
        "2.0.0",
        "2.0.0rc1",
        "2.0.0rc2",
        "2.0.0rc3",
        "2.0.0rc4",
        "2.0.0rc5",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.1.0",
        "2.1.1",
        "2.1.2",
        "2.2.0",
        "2.2.0a1",
        "2.2.1",
        "2.2.2",
        "2.2.3",
        "2.3.0",
        "2.3.1",
        "2.3.2",
        "2.3.3",
        "2.3.4",
        "2.3.5",
        "2.3.6",
        "2.3.7",
        "2.3.8",
        "3.0.0",
        "3.0.1",
        "3.0.2",
        "3.0.3",
        "3.0.4",
        "3.0.5",
        "3.0.6",
        "3.1.0",
        "3.1.1",
        "3.1.2",
        "3.1.3",
        "3.1.4",
        "3.1.5"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27199",
    "GHSA-29vq-49wr-vm6x"
  ],
  "details": "Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safe_join accepts paths with multiple segments, such as example/NUL. The function send_from_directory uses safe_join to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6.",
  "id": "PYSEC-2026-2320",
  "modified": "2026-07-13T05:52:35.507466Z",
  "published": "2026-02-21T06:17:00.710Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/pallets/werkzeug/releases/tag/3.1.6"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6x"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d9338d"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ]
}



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