Auth bypass in Discourse
CVE-2026-91157
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Discourse — versions < 2026.1.9, >= 2026.7.0-latest, < 2026.7.3, >= 2026.8.0-latest, < 2026.8.1
Weakness classification (CWE)
References
- github.com/discourse/discourse/security/advisories/GHSA-298h-xgw6-4pv3
- github.com/discourse/discourse/commit/16017732981fdb3ee65d7b3c69c573610bf02aab
- github.com/discourse/discourse/commit/83f5f9f1df7ddc79ec0950e1b2038ba659635708
- github.com/discourse/discourse/commit/98f1c021d0e956cded5239a5d8a6afe2b9e1b7e7
- github.com/discourse/discourse/commit/b2fb98394b2636b29e850f06b0029f8ca8b48458
Frequently asked questions
- What is CVE-2026-91157?
- CVE-2026-91157 is a high-severity vulnerability in Discourse, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-10-14.
- How severe is CVE-2026-91157?
- High severity. CVSS v3 base score is 7.5 out of 10.