SSRF in Zitadel

CVE-2026-55671

ZITADEL is an open source identity management platform. From 4.0.0-rc.1 through 4.15.1, ZITADEL's HTTP notification channels, OIDC BackChannel Logout, and SAML metadata URL fetches do not consistently validate user-defined URLs against protected denylist handling, allowing server-side requests to loopback, internal IP, link-local, or redirected endpoints through DNS rebinding, redirects, or protocol downgrades. This issue is fixed in version 4.15.2.

Vulnerability class: SSRF (Server-Side Request Forgery)

EPSS: 0.004 (34.1th percentile) — read the EPSS interpretation.