Description
Discourse is an open source discussion platform. A vulnerability present in versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 affects anyone who uses S3 for uploads. While scripts may be executed, they will only be run in the context of the S3/CDN domain, with no site credentials. Versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 fix the issue. As a workaround, disallow html or xml files for uploads in authorized_extensions. For existing html xml uploads, site owners can consider deleting them.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
- Attack Vector
- network
- Complexity
- low
- Privileges
- low
- User Action
- required
- Scope
- unchanged
- Confidentiality
- none
- Integrity
- low
- Availability
- low
- Weaknesses
- CWE-116
Metadata
- Primary Vendor
- DISCOURSE
- Published
- 1/28/2026
- Last Modified
- 1/30/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
discourse : discoursediscourse : discoursediscourse : discoursediscourse : discourse
AI-Powered Remediation
Generate remediation guidance or a C-suite brief for this vulnerability.