Discourse 2026.x Arbitrary Outbound Connections via Group Email Test Endpoint
CVE-2026-33185 Published on March 31, 2026
Discourse: Group SMTP test endpoint susceptible to SSRF
Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, the group email settings test endpoint could be used to make the server initiate outbound connections to arbitrary hosts and ports. This could allow probing of internal network infrastructure. The endpoint was accessible to non-staff group owners. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2026-33185 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2026-33185
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Affected Versions
discourse:- Version >= 2026.1.0-latest, < 2026.1.3 is affected.
- Version >= 2026.2.0-latest, < 2026.2.2 is affected.
- Version >= 2026.3.0-latest, < 2026.3.0 is affected.