ubuntu-cve-2025-47278
Vulnerability from osv_ubuntu
Published
2025-05-13 16:15
Modified
2025-09-08 17:11
Summary
Details

Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the itsdangerous library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Flask was incorrectly constructing that list in reverse, passing the signing key first. Sites that have opted-in to use key rotation by setting SECRET_KEY_FALLBACKS care likely to unexpectedly be signing their sessions with stale keys, and their transition to fresher keys will be impeded. Sessions are still signed, so this would not cause any sort of data integrity loss. Version 3.1.1 contains a patch for the issue.

Severity
1.8 (Low)
CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-flask",
            "binary_version": "3.1.0-2ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.04",
        "name": "flask",
        "purl": "pkg:deb/ubuntu/flask@3.1.0-2ubuntu1.1?arch=source\u0026distro=plucky"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.0-2ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.3-1ubuntu1",
        "3.1.0-2ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "Flask is a web server gateway interface (WSGI) web application framework. In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing key. Signing is provided by the `itsdangerous` library. A list of keys can be passed, and it expects the last (top) key in the list to be the most recent key, and uses that for signing. Flask was incorrectly constructing that list in reverse, passing the signing key first. Sites that have opted-in to use key rotation by setting `SECRET_KEY_FALLBACKS` care likely to unexpectedly be signing their sessions with stale keys, and their transition to fresher keys will be impeded. Sessions are still signed, so this would not cause any sort of data integrity loss. Version 3.1.1 contains a patch for the issue.",
  "id": "UBUNTU-CVE-2025-47278",
  "modified": "2025-09-08T17:11:57Z",
  "published": "2025-05-13T16:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2025-47278"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-47278"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pallets/flask/security/advisories/GHSA-4grg-w6v8-c28g"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pallets/flask/commit/73d6504063bfa00666a92b07a28aaf906c532f09"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pallets/flask/releases/tag/3.1.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-7534-1"
    }
  ],
  "related": [
    "USN-7534-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2025-47278"
  ],
  "withdrawn": "2026-01-20T05:33:07Z"
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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