CVE-2025-66488

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.

PUBLISHED Reserved 2025-12-02 | Published 2026-01-28 | Updated 2026-01-28 | Assigner GitHub_M

Problem types

CWE-116: Improper Encoding or Escaping of Output

Product status

References

github.com/...course/security/advisories/GHSA-68jp-3934-62rx

cve.org (CVE-2025-66488)

nvd.nist.gov (CVE-2025-66488)

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