CVE-2026-91156
highDiscourse is an open-source discussion platform.
Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, MessageBus audience calculation could deliver messages from a read-restricted category chat channel to an authenticated user who could view the category but was not allowed to use Chat under the site's group restrictions. The publication path bounded events by category visibility without also enforcing Chat eligibility, exposing live and recent message content available in the MessageBus backlog. The issue does not permit retrieval of the channel's full history through the Chat API and does not permit message creation or modification. This issue is fixed in versions 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/discourse/discourse/commit/046fb7bfd68a5b95e63dda88c3c73877c5cf9d5e security-advisories@github.com
- https://github.com/discourse/discourse/commit/87b31bf60a7827f075634254379a1dcbaba409cb security-advisories@github.com
- https://github.com/discourse/discourse/commit/ba74bb404ab4439f5b1f0204e848d62099db8ae1 security-advisories@github.com
- https://github.com/discourse/discourse/commit/cac1f26f275cec3dc1dd51dfdac2b3d1a4ec50f8 security-advisories@github.com
- https://github.com/discourse/discourse/security/advisories/GHSA-gh4f-qr62-vx8q security-advisories@github.com