What’s Vulnerable › Vulnerabilities

CVE-2026-18967: Keycloak-services: keycloak-services: saml onetimeuse assertion replay in idp-initiated broker flow

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-06 · updated 2026-08-10
• Weakness: CWE-294

Description

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.

Affected products

• Red Hat build of Keycloak 26.4: all versions
• RedHat Jboss Enterprise Application Platform Expansion Pack: all versions

References

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

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