Vulnerability in Red Hat Build Of Keycloak
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (14.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-18967 (vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (Permissions Required, issue-tracking)
Frequently asked questions
- What is CVE-2026-18967?
- CVE-2026-18967 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Authentication Bypass by Capture-replay. CVSS score: 6.4/10. Published 2026-08-06.
- How severe is CVE-2026-18967?
- Medium severity. CVSS v3 base score is 6.4 out of 10.