What’s Vulnerable › Vulnerabilities

CVE-2026-0707: Keycloak: keycloak authorization header parsing leading to potential security control bypass

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-08 · updated 2026-10-26
• Weakness: CWE-551

Description

A flaw was found in Keycloak. The Keycloak Authorization header parser is overly permissive regarding the formatting of the "Bearer" authentication scheme. It accepts non-standard characters (such as tabs) as separators and tolerates case variations that deviate from RFC 6750 specifications.

Affected products

• Red Hat build of Keycloak 26.4: all versions — fixed in 26.4-12, 26.4.10-1

How to fix

Upgrade to a fixed version: Red Hat build of Keycloak 26.4 26.4-12, 26.4.10-1. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/errata/RHSA-2026:3947
• https://access.redhat.com/errata/RHSA-2026:3948
• https://access.redhat.com/security/cve/CVE-2026-0707
• https://bugzilla.redhat.com/show_bug.cgi?id=2427768
• https://github.com/keycloak/keycloak/issues/49433

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