CVE-2026-91157highCWE-200CWE-863

CVE-2026-91157: high-severity vulnerability in discourse

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

Published · Updated

Follow this CVE+ Monitor discourse

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.5epss 0.5%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected products
discourse · discourse
Related CVEs — discourse

In the same product, most dangerous first.

CVE-2024-53991HIGHPotential Backup file leaked via Nginx in DiscourseEPSS 29.9%CVE-2021-41163CRITICALRCE via malicious SNS subscription payloadEPSS 19.8%CVE-2023-45131HIGHUnauthenticated access to new private chat messages in DiscourseEPSS 4.0%CVE-2026-28227LOWDiscourse Vulnerable to Unauthorized Topic Creation in Staff-Only Categories via Topic Timer publish_to_categoryEPSS 3.3%CVE-2022-36066CRITICALDiscourse vulnerable to RCE via admins uploading maliciously zipped fileEPSS 2.1%CVE-2024-47773HIGHAnonymous cache poisoning via XHR requests in DiscourseEPSS 1.8%