Discourse: Open redirect via `sso_destination_url` cookie in `enter`
33Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 5.1epss 0.2%
exploitation probability
0.2%top 91% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
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 enter action in StaticController reads the sso_destination_url cookie and redirects to it with allow_other_host: true without validating the destination URL. While this cookie is normally set during legitimate DiscourseConnect Provider flows with cryptographically validated SSO payloads, cookies are client-controlled and can be set by attackers. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
Affected products
discourse · discoursepublic PoCs found — 1
cve_referencemeta.discourse.org/t/use-discourse-as-an-identity-provider-sso-discourseconnect/32974unverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://github.com/discourse/discourse/commit/080408b93d00305b51d71f63f755f43fa601884dhttps://github.com/discourse/discourse/security/advisories/GHSA-378j-ccw4-4fwhhttps://meta.discourse.org/t/use-discourse-as-an-identity-provider-sso-discourseconnect/32974https://meta.discourse.org/t/using-discourse-as-a-sso-provider/32974