GHSA-4grg-w6v8-c28g

Source

https://github.com/advisories/GHSA-4grg-w6v8-c28g

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/05/GHSA-4grg-w6v8-c28g/GHSA-4grg-w6v8-c28g.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-4grg-w6v8-c28g

Aliases

CVE-2025-47278

Published

2025-05-13T20:25:26Z

Modified

2025-05-13T20:43:20.990853Z

Severity

1.8 (Low) CVSS_V4 - 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 CVSS Calculator

Summary

Flask uses fallback key instead of current signing key

Details

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 are 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.

Database specific

{
    "nvd_published_at": "2025-05-13T16:15:32Z",
    "cwe_ids": [
        "CWE-683"
    ],
    "severity": "LOW",
    "github_reviewed": true,
    "github_reviewed_at": "2025-05-13T20:25:26Z"
}

GHSA-4grg-w6v8-c28g

Affected packages

PyPI / flask

Package

Affected ranges

Affected versions

3.*