Discourse is an open-source discussion platform. From versions 2026.1.0 to before 2026.1.3, and 2026.2.0 to before 2026.2.2, the enter action in StaticController reads the ssodestinationurl cookie and redirects to it with allowotherhost: 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.
{
"cpes": [
"cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"
],
"severity": "Medium"
}