CVE-2026-91157
Description
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, sites with secure uploads enabled did not reconcile existing upload security metadata when a previously public category became read-restricted or when category permissions changed during a bulk import. Media and attachments uploaded while the category was public retained a public accessibility flag and remained reachable by anonymous users through their short upload URLs, including uploads associated with deleted topics. This issue is fixed in versions 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/discourse/discourse/commit/16017732981fdb3ee65d7b3c69c573610bf02aab
- https://github.com/discourse/discourse/commit/83f5f9f1df7ddc79ec0950e1b2038ba659635708
- https://github.com/discourse/discourse/commit/98f1c021d0e956cded5239a5d8a6afe2b9e1b7e7
- https://github.com/discourse/discourse/commit/b2fb98394b2636b29e850f06b0029f8ca8b48458
- https://github.com/discourse/discourse/security/advisories/GHSA-298h-xgw6-4pv3
CWEs
CWE-200 CWE-863
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.