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.
History

Thu, 06 Aug 2026 06:30:00 +0000

Type Values Removed Values Added
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.
Title Keycloak-services: keycloak-services: saml onetimeuse assertion replay in idp-initiated broker flow
First Time appeared Redhat
Redhat build Keycloak
Redhat jbosseapxp
Redhat red Hat Single Sign On
Weaknesses CWE-294
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 6.4, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-08-06T05:33:17.868Z

Reserved: 2026-08-05T15:22:29.997Z

Link: CVE-2026-18967

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-06T07:30:16Z