CVE-2026-18967
Keycloak-services: keycloak-services: saml onetimeuse assertion replay in idp-initiated broker flow
- State
- Published
- Severity
- 6.4 Medium
- Published
- Aug 6, 2026
- Updated
- Aug 6, 2026
- Reserved
- Aug 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.4 Medium | CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N | redhat |
Weaknesses
- CWE-294 Authentication Bypass by Capture-replay
Affected Products
| Product | Versions |
|---|---|
Red Hat Build of KeycloakRed Hat | |
Red Hat Build of KeycloakRed Hat | |
Red Hat Build of KeycloakRed Hat | |
Red Hat JBoss Enterprise Application Platform Expansion PackRed Hat | |
Red Hat Single Sign-On 7Red Hat |
References
- https://access.redhat.com/security/cve/CVE-2026-18967vdb-entry
- RHBZ#2511604issue-tracking
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