Discourse: Non-participant moderators can read, edit, and delete PM content through Discourse AI reviewables
Key facts
- Attack vector
- Network
- Privileges required
- High
- User interaction
- Required
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-862.
Summary
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Discourse AI reviewables associated with private messages could appear in the moderator review queue of a moderator who was not a participant in the message. Reviewable visibility filtering did not restrict private-message reviewables to the audience permitted to access the underlying private-message topic, allowing the moderator to read otherwise confidential content. Depending on the available reviewable action, the moderator could also modify the private message by closing its topic or deleting a post. Exploitation requires an authenticated moderator account and a pre-existing Discourse AI reviewable associated with a private message. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| discourse | discourse | before 2026.7.0; 2026.6.0-latest to before 2026.6.1; 2026.5.0-latest to before 2026.5.2; 2026.1.0-latest to before 2026.1.6 | 2026.7.0, 2026.6.1, 2026.5.2, 2026.1.6 | Patch available | CNA |
- discourse Vendordiscourse Affected before 2026.7.0; 2026.6.0-latest to before 2026.6.1; 2026.5.0-latest to before 2026.5.2; 2026.1.0-latest to before 2026.1.6 Fixed in 2026.7.0, 2026.6.1, 2026.5.2, 2026.1.6 Patch available CNA
Remediation
- Fix · CNA discourse (discourse) Fixed in 2026.7.0, 2026.6.1, 2026.5.2, 2026.1.6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-84302
References
Other 6
- https://github.com/discourse/discourse/security/advisories/GHSA-3rx9-fqgh-wfpc
- https://github.com/discourse/discourse/pull/42091
- https://github.com/discourse/discourse/commit/1566d04524c01472375944bbf7b198dd09a99427
- https://github.com/discourse/discourse/commit/23488b72a200228e805c4e6d970fbad216d328c5
- https://github.com/discourse/discourse/commit/38d10c0e5d1b76540d2860455e0290f8e975c9fd
- https://github.com/discourse/discourse/commit/b323702d87cd82c327c116d9566477f3c4f9635f
More discourse vulnerabilities
- TI-2022-22806 Discourse BBCode plugin vulnerable to arbitrary CSS injection CVSS 3.1CRITICAL 9.8
- TI-2021-19656 Denial of Service in discourse CVSS 3.1MEDIUM 6.8
- TI-2024-36150 Potential Backup file leaked via Nginx in Discourse CVSS 3.1HIGH 7.5
- TI-2021-18002 RCE via malicious SNS subscription payload CVSS 3.1CRITICAL 10.0
- TI-2026-24651 Discourse: Open redirect via `sso_destination_url` cookie in `enter` CVSS 4.0MEDIUM 5.1
- TI-2022-18730 Discourse Patreon vulnerable to improper validation of email during Patreon authentication CVSS 3.1CRITICAL 9.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences