Improper access control in Discourse - CVE-2026-27934
Published: July 1, 2026
Vulnerability identifier: #VU136160
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-27934
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 attacker to disclose sensitive information.
The vulnerability exists due to improper access control in the user action API endpoint when handling requests for user actions. A remote attacker can request user action data to disclose sensitive information.
The issue may expose the title and post excerpt of private topics to unauthorized users.
How to mitigate CVE-2026-27934
Install security update from vendor's website.