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HIGH severity

Authentication Bypass in keycloakGHSA-m9cj-v55f-8x26

HIGHFix: keycloak/keycloak@dae4a3e

GHSA-m9cj-v55f-8x26 is a high-severity (CVSS 8.8) CWE-250 vulnerability in org.keycloak:keycloak-core. A fix is available for org.keycloak:keycloak-core — see the affected versions and patch details below.

Also known asCVE-2020-27826
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk
0.00%0.36%0.71%1.07%0.2%0.6%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

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 flaw was found in Keycloak before version 12.0.0 where it is possible to update the user's metadata attributes using Account REST API. This flaw allows an attacker to change its own NameID attribute to impersonate the admin user for any particular application.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.keycloak:keycloak-coreall versions12.0.0org.keycloak:keycloak-core:12.0.0

Affected Products

2 products · 4 configurations
Application
keycloakredhat
< 12.0.0
range
Application
single sign-onredhat
2 versions
7.47.4.4

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 12.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m9cj-v55f-8x26 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 HatLow
ProductFixed inAdvisory
Red Hat Single Sign-On 7see advisoryRHSA-2020:5533
Red Hat Single Sign-On 7.4 for RHEL 6rh-sso7-keycloak-0:9.0.10-1.redhat_00001.1.el6ssoRHSA-2020:5526
Red Hat Single Sign-On 7.4 for RHEL 7rh-sso7-keycloak-0:9.0.10-1.redhat_00001.1.el7ssoRHSA-2020:5527
Red Hat Single Sign-On 7.4 for RHEL 8rh-sso7-keycloak-0:9.0.10-1.redhat_00001.1.el8ssoRHSA-2020:5528

Frequently Asked Questions

A flaw was found in Keycloak before version 12.0.0 where it is possible to update the user's metadata attributes using Account REST API. This flaw allows an attacker to change its own NameID attribute to impersonate the admin user for any particular application.
O3 Security · Impact-Aware SCA

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Authentication Bypass in keycloak (High 8.8)