CVE-2025-66488 json
Discourse allows script execution in uploaded HTML/XML files on S3
published 9mo ago modified 2mo ago also BIT-discourse-2025-66488 , EUVD-2025-206449 , GHSA-68jp-3934-62rx
- cvss
- 4.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 9%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- bitnami discourse 3.5.4, 2025.11.2, 2025.12.1, 2026.1.0
- discourse discourse 3.5.4, 2025.11.2, 2025.12.1, 2026.1.0
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 9mo ago
Exploit prediction
0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| OSV | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | discourse | <3.5.4 >=2025.11.0, <2025.11.2 >=2025.12.0, <2025.12.1 >=2026.1.0, <2026.1.0 |
3.5.4 2025.11.2 2025.12.1 2026.1.0 |
Affected products
- discourse discourse
Classification
- Weakness
-
- CWE-116 Improper Encoding or Escaping of Output
References
-
github.com
/discourse/discourse/security/advisories/GHSA-68jp-3934-62rx
third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-66488
web
Sources
- CVE List CVE-2025-66488
- NVD CVE-2025-66488
- OSV BIT-discourse-2025-66488
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.