Discourse: Review queue exposes flag-related private message excerpts to category group moderators
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · 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 2026.7.1, on sites with category group moderation enabled, the review queue could include an excerpt (and permalink) of the private message attached to a flag, even when the reviewing category moderator was not a participant in that message. These notify_moderators flag messages are addressed only to moderators and, for core flags, to a category's moderation groups as they existed when the flag was raised, so a category group moderator could read flag-discussion content they were not authorized to see. This affects official plugins that create such messages and core flags raised before a moderator's group was granted moderation of the category. Only the confidentiality of a limited excerpt of these flag-related private messages is affected; no content can be modified or deleted. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.1.
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 | 2026.1.0-latest to before 2026.1.6; 2026.5.0-latest to before 2026.5.2; before 2026.6.1 | 2026.1.6, 2026.5.2, 2026.6.1 | Patch available | CNA |
- discourse Vendordiscourse Affected 2026.1.0-latest to before 2026.1.6; 2026.5.0-latest to before 2026.5.2; before 2026.6.1 Fixed in 2026.1.6, 2026.5.2, 2026.6.1 Patch available CNA
Remediation
- Fix · CNA discourse (discourse) Fixed in 2026.1.6, 2026.5.2, 2026.6.1
Timeline
- 2026-10-02 Threatist record created from CVE-2026-59829
References
Other 6
- https://github.com/discourse/discourse/security/advisories/GHSA-wmc6-pmxp-xw5w
- https://github.com/discourse/discourse/pull/41527
- https://github.com/discourse/discourse/commit/4df0e54f59361c78606b578ad12a2c39b4dd9f59
- https://github.com/discourse/discourse/commit/58e45dc7c92d19d5294c73fbcd3833c73dc51754
- https://github.com/discourse/discourse/commit/74c8522a197658c69b0adefa182f601ce85dcefa
- https://github.com/discourse/discourse/commit/e56bd3ec58ae387946220821d1ce214eed02d1b9
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