Server-Side Request Forgery (SSRF) in Discourse - CVE-2026-33185
Published: July 1, 2026
Vulnerability identifier: #VU136145
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-2026-33185
CWE-ID: CWE-918
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 probe internal network infrastructure.
The vulnerability exists due to server-side request forgery (SSRF) in the group email settings test endpoint when handling test requests. A remote user can submit a crafted request to make the server initiate outbound connections to arbitrary hosts and ports to probe internal network infrastructure.
The endpoint was accessible to non-staff group owners.
How to mitigate CVE-2026-33185
Install security update from vendor's website.