Discourse: Signup-time primary_group_id assignment grants whisperer access
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Privilege escalation
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-269.
Summary
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the signup flow could allow newly registered users to set primary_group_id and gain whisper-group privileges without legitimate group membership on sites with whispers_allowed_groups configured. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 2026.1.5; 2026.4.0-latest to before 2026.4.2; 2026.5.0-latest to before 2026.5.1 | 2026.1.5, 2026.4.2, 2026.5.1 | Patch available | CNA |
- discourse Vendordiscourse Affected 2026.1.0-latest to before 2026.1.5; 2026.4.0-latest to before 2026.4.2; 2026.5.0-latest to before 2026.5.1 Fixed in 2026.1.5, 2026.4.2, 2026.5.1 Patch available CNA
Remediation
- Fix · CNA discourse (discourse) Fixed in 2026.1.5, 2026.4.2, 2026.5.1
Timeline
- 2026-10-02 Threatist record created from CVE-2026-44787
- 2026-10-14 EPSS moved to the 50th–90th percentile
References
Patch 4
- https://github.com/discourse/discourse/commit/012796ac28c85b30aa233c5ef042fc66efff8126
- https://github.com/discourse/discourse/commit/0f50a07a6ef4b33f3f826ce6d7bf6d7bd16912d8
- https://github.com/discourse/discourse/commit/5418e3027dba109e27a4796463686d61e190ac29
- https://github.com/discourse/discourse/commit/6fc7e6cf04422fc3f9d1c99134803071e983ff0a
More Discourse vulnerabilities
- 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-2026-22278 Discourse leaks private topic title and post excerpt via user action API endpoint CVSS 4.0HIGH 8.7
- TI-2023-24152 Unauthenticated access to new private chat messages in Discourse CVSS 3.1HIGH 7.5
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences