Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

Advisory record · GHSA-5v8v-xvjv-57x7

Keycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim

CVSS 3.7 LowEPSS 0.0026 · 17th percentile

Published by the GitHub Advisory Database at 6 Apr 2026, 09:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
org.keycloak:keycloak-servicesMaven<26.4.13 || >=26.5.0, <26.6.326.4.13, 26.6.3
Identifiers
GHSA-5v8v-xvjv-57x7 · CVE-2026-37977
Weakness (CWE)
CWE-346
Tags
Published
6 Apr 2026
Updated
15 Jul 2026

Machine-written summary

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

Keycloak's keycloak-services package, versions before 26.4.13 and from 26.5.0 before 26.6.3, can reflect an attacker-chosen origin in the CORS header on the UMA token endpoint before the JWT signature is checked. A remote attacker could use this to read low-sensitivity information from error responses, but only when a target client is configured with webOrigins set to "*". Upgrade to 26.4.13 or 26.6.3.

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
3.7 Low 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N CNA (redhat)
  • CISA KEV Not listed.
  • EPSS 0.0026, the 17th percentile, on 11 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.