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HIGH severity

GHSA-4pc7-vqv5-5r3v — keycloak-saml-core

HIGHFix: keycloak/keycloak@44000ca

GHSA-4pc7-vqv5-5r3v is a high-severity (CVSS 8.1) Improper Authentication vulnerability in org.keycloak:keycloak-saml-core. A fix is available for org.keycloak:keycloak-saml-core — see the affected versions and patch details below.

ECP SAML binding bypasses authentication flows

Also known asCVE-2021-3827
Published
Apr 27, 2022
Updated
Jul 8, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-4pc7-vqv5-5r3v plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
☕org.keycloak:keycloak-saml-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

Description

A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.keycloak:keycloak-saml-coreall versions18.0.0org.keycloak:keycloak-saml-core:18.0.0

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-saml-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.keycloak:keycloak-saml-core to 18.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4pc7-vqv5-5r3v 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4pc7-vqv5-5r3v can be triaged on real exposure rather than presence alone.

Tailored to GHSA-4pc7-vqv5-5r3v. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

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 HatModerate
ProductFixed inAdvisory
Red Hat Single Sign-On 7.5 for RHEL 7rh-sso7-keycloak-0:15.0.4-1.redhat_00001.1.el7ssoRHSA-2022:0151
Red Hat Single Sign-On 7.5 for RHEL 8rh-sso7-keycloak-0:15.0.4-1.redhat_00001.1.el8ssoRHSA-2022:0152
RHEL-8 based Middleware Containersrh-sso-7/sso75-openshift-rhel8:7.5-15RHSA-2022:0164
RHSSO 7.5.1keycloak-server-spi-privateRHSA-2022:0155

Frequently Asked Questions

### Description A flaw was found in keycloak, where the default ECP binding flow allows other authentication flows to be bypassed. By exploiting this behavior an attacker can bypass the MFA authentication by sending a SOAP request with an AuthnRequest and Authorization header with the user's credentials. The highest threat from this vulnerability is to confidentiality and integrity.
O3 Security · Impact-Aware SCA

Is GHSA-4pc7-vqv5-5r3v in your dependencies?

O3 Security finds GHSA-4pc7-vqv5-5r3v across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-4pc7-vqv5-5r3v: keycloak-saml-core | O3 Security