All vulnerabilities
CVE-2026-91157GHSA-298h-xgw6-4pv3

Discourse: Media uploads remain publicly accessible after category permissions are restricted

discourse discourseApplications & CMS
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.48%Chance of exploitation activity in the next 30 days, higher than 40% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published14 Oct 2026Updated 20 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 4

  • discourseaffected: < 2026.1.9CVE List
  • discourseaffected: >= 2026.7.0-latest, < 2026.7.3CVE List
  • discourseaffected: >= 2026.8.0-latest, < 2026.8.1CVE List
  • discourseaffected: >= 2026.9.0-latest, < 2026.9.0CVE List

References 5