CVE catalog

CVE-2026-11800

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forgi

[CVE catalog]

Severity
High · CVSS 8.1CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published
Source
[NVD] · [CVE record]
EPSS
0.30% · Oct 25, 2026

A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Cpebuild_of_keycloakNot reported26.6.4fixed
Cpebuild_of_keycloakNot reported26.6.4fixed

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Cpebuild_of_keycloakcpeNot reported26.6.4Not reportedNot reportedNot reported
Cpebuild_of_keycloakcpeNot reported26.6.4Not reportedNVD-CVE-2026-11800Not reported

OpenFactory catalog packages

No matching packages in this catalog.

Observed:

References

[CERT-Bund public advisories] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [Red Hat security advisories and VEX]