CVE-2026-18967

A flaw was found in the SAML broker component of Keycloak, an identity and access management solution. When configured as a SAML broker using the IdP-Initiated flow, Keycloak fails to enforce the OneTimeUse condition in SAML assertions. This allows an attacker who captures a valid, unused assertion to replay it multiple times. Successful exploitation could allow an attacker to hijack a user's session and gain unauthorized access to the system as that user.

CVSS vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

• https://access.redhat.com/security/cve/CVE-2026-18967
• https://bugzilla.redhat.com/show_bug.cgi?id=2511604