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Advisory record · GHSA-4x37-hw65-52w8

Keycloak: Information disclosure via OIDC token introspection endpoint audience bypass

CVSS 6.5 MediumEPSS 0.0037 · 30th percentile

Published by the GitHub Advisory Database at 19 May 2026, 12:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
org.keycloak:keycloak-servicesMaven<26.6.226.6.2
Identifiers
GHSA-4x37-hw65-52w8 · BIT-keycloak-2026-37979 · CVE-2026-37979
Weakness (CWE)
CWE-284 · CWE-639
Tags
Published
19 May 2026
Updated
26 Aug 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Keycloak (org.keycloak:keycloak-services) versions before 26.6.2 are vulnerable. A confidential client with valid credentials can bypass audience restrictions on the OIDC token introspection endpoint and retrieve sensitive claims from tokens meant for other resource servers. Upgrade to version 26.6.2 or later.

Written 2 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
6.5 Medium 3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N CNA (redhat)
  • CISA KEV Not listed.
  • EPSS 0.0037, the 30th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:19 UTC First seen by agentprime
  2. 31 Oct 2026, 14:19 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.