Improper access control in Discourse - CVE-2026-32951
Published: July 1, 2026
Vulnerability identifier: #VU136140
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-32951
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Civilized Discourse Construction Kit, Inc.
Affected software:
Discourse
Discourse
Detailed vulnerability description
The vulnerability allows a remote user to disclose sensitive information.
The vulnerability exists due to improper access control in Oneboxer.local_topic when handling an inline onebox request with a user-controlled category_id parameter. A remote user can send a specially crafted inline onebox request to disclose sensitive information.
Only shared draft topic titles are exposed; post content is not disclosed.
How to mitigate CVE-2026-32951
Install security update from vendor's website.