Incorrect authorization in Discourse - CVE-2026-33410
Published: July 1, 2026
Vulnerability identifier: #VU136127
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-33410
CWE-ID: CWE-863
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 the chat direct message API when creating a direct message channel or adding users to an existing one. A remote user can send a specially crafted API request with a known private or hidden group name to disclose sensitive information.
The issue can expose the identities of members of private or hidden groups.
How to mitigate CVE-2026-33410
Install security update from vendor's website.