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Description

FlaskBB through 2.2.0, fixed in commit a5da9a5, contains a logic flaw vulnerability that allows authenticated administrators to delete all built-in authorization groups by exploiting a type mismatch in the bulk delete protection check. The bulk AJAX endpoint in the management views compares received JSON integer group IDs against string literals, causing the protection check to always pass, which allows deletion of all six built-in groups and destroys the forum's permission model, potentially rendering the site unusable.

PUBLISHED Reserved 2026-01-08 | Published 2026-07-10 | Updated 2026-07-14 | Assigner VulnCheck




HIGH: 8.6CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

HIGH: 7.2CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Problem types

Incorrect Comparison

Product status

Default status
affected

Any version
affected

https://github.com/flaskbb/flaskbb/commit/a5da9a52 (git)
unaffected

Credits

Hamed Kohi (@0xHamy) finder

VulnCheck coordinator

References

github.com/...laskbb/security/advisories/GHSA-r9cf-jxr6-5h3r exploit

github.com/...laskbb/security/advisories/GHSA-r9cf-jxr6-5h3r (GitHub Security Advisory (GHSA-r9cf-jxr6-5h3r)) vendor-advisory

github.com/...ommit/a5da9a529adddc65fe31e275192b642a4e32de64 (Patch Commit) patch

www.vulncheck.com/...n-group-deletion-via-bulk-ajax-endpoint third-party-advisory

cve.org (CVE-2026-22660)

nvd.nist.gov (CVE-2026-22660)

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