CVE-2025-66488
Discourse allows script execution in uploaded HTML/XML files on S3
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 4.6EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
28 Jan 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
Affected products
discourse · discourseWant to know if your infrastructure is exposed to this?
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