Auth bypass in Flaskbb
CVE-2026-22659
FlaskBB through 2.2.0, fixed in commit acc88cf, contains an authorization bypass vulnerability that allows authenticated moderators to perform unauthorized actions on topics in forums they do not control by submitting crafted topic ID lists. Attackers can include a low-ID topic from a permitted forum as an anchor in a batch request, causing the permission check applied only to the first result to pass, and then execute lock, unlock, delete, or hide actions against topics in unmoderated forums.
Vulnerability class: Broken Access Control
EPSS: 0.003 (21.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H.
Affected products
- Flaskbb — versions 0, https://github.com/flaskbb/flaskbb/commit/a5da9a52
Weakness classification (CWE)
References
- disclosure@vulncheck.com (vendor-advisory)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-22659?
- CVE-2026-22659 is a high-severity vulnerability in Flaskbb, classified under Incorrect Authorization. CVSS score: 8.1/10. Published 2026-07-10.
- How severe is CVE-2026-22659?
- High severity. CVSS v3 base score is 8.1 out of 10.