Server-Side Request Forgery (SSRF) in Discourse - CVE-2023-28112
Published: March 17, 2023 / Updated: July 1, 2026
Vulnerability identifier: #VU136080
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2023-28112
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 trigger outbound network connections to private IP addresses from the server.
The vulnerability exists due to improper access control in FastImage requests when processing user-supplied URLs. A remote user can supply a crafted URL to trigger outbound network connections to private IP addresses from the server.
The issue affects some user-provided URLs that were passed to FastImage without SSRF protection.
How to mitigate CVE-2023-28112
Install security update from vendor's website.