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☕ Maven
Not in CISA KEV
HIGH severity

CVE-2024-10039 — keycloak-core

HIGH

CVE-2024-10039 is a high-severity (CVSS 7.1) vulnerability in org.keycloak:keycloak-core. A fix is available for org.keycloak:keycloak-core — see the affected versions and patch details below.

Keycloak mTLS Authentication Bypass via Reverse Proxy TLS Termination

Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 10, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
☕org.keycloak:keycloak-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

A vulnerability was found in Keycloak. Deployments of Keycloak with a reverse proxy not using pass-through termination of TLS, with mTLS enabled, are affected. This issue may allow an attacker on the local network to authenticate as any user or client that leverages mTLS as the authentication mechanism.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.keycloak:keycloak-coreall versions26.0.6org.keycloak:keycloak-core:26.0.6

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.keycloak:keycloak-core to 26.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-10039 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Red Hat Enterprise Application Platform does not ship the Keycloak server code and thus is not affected by this vulnerability. The candlepin package ships Keycloak client libraries, including keycloak-core, to validate OpenID Connect tokens against an external identity provider. It does not ship the Keycloak server,…

ProductFixed inAdvisory
Red Hat build of Keycloak 24rhbk/keycloak-operator-bundle:24.0.9-1RHSA-2024:10175
Red Hat build of Keycloak 24.0.9see advisoryRHSA-2024:10176
Red Hat build of Keycloak 26.0rhbk/keycloak-operator-bundle:26.0.6-2RHSA-2024:10177
Red Hat build of Keycloak 26.0.6see advisoryRHSA-2024:10178
Red Hat Single Sign-On 7see advisoryRHSA-2025:11645

Frequently Asked Questions

A vulnerability was found in Keycloak. Deployments of Keycloak with a reverse proxy not using pass-through termination of TLS, with mTLS enabled, are affected. This issue may allow an attacker on the local network to authenticate as any user or client that leverages mTLS as the authentication mechanism.
O3 Security · Impact-Aware SCA

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