HIGHCVSS 8.1EPSS 0.3%

CVE-2026-11800

CVE-2026-11800 updated by NVD

Published: 2026-11-03
Modified: 2026-11-03
EPSS percentile: 23%
Sources: github-advisory, nvd

Summary

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.

Affected packages

Ecosystem	Package	Affected versions	Fixed versions
Maven	org.keycloak:keycloak-services	—	26.6.4

Remediation: Upgrade to 26.6.4 or later.

References

https://nvd.nist.gov/vuln/detail/CVE-2026-11800

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

Includes data from the National Vulnerability Database (NIST). NVD data is in the public domain; this page is not endorsed by NIST.

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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.