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HIGH severity

CVE-2021-21678 — saml

HIGHFix: jenkinsci/saml-plugin@e063317

CVE-2021-21678 is a high-severity (CVSS 8.8) Cross-Site Request Forgery (CSRF) vulnerability in org.jenkins-ci.plugins:saml. A fix is available for org.jenkins-ci.plugins:saml — see the affected versions and patch details below.

Jenkins SAML Plugin allows bypassing CSRF protection for any URL

Also known asGHSA-r5w3-pfq8-3r82
Published
Aug 31, 2021
Updated
Jul 9, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs55th percentile — riskier than 55% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-21678 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
☕org.jenkins-ci.plugins:saml

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

An extension point in Jenkins allows selectively disabling cross-site request forgery (CSRF) protection for specific URLs. SAML Plugin implements this extension point for the URL that users are redirected to after login.

In Jenkins SAML Plugin 2.0.7 and earlier this implementation is too permissive, allowing attackers to craft URLs that would bypass the CSRF protection of any target URL.\n\nThis vulnerability was originally introduced in Jenkins SAML Plugin 1.1.3.

Jenkins SAML Plugin 2.0.8 restricts which URLs it disables cross-site request forgery (CSRF) protection for to the one URL that needs it.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.jenkins-ci.plugins:samlall versions2.0.8org.jenkins-ci.plugins:saml:2.0.8

Affected Products

1 product · 1 configurations
Application
samljenkins
≥ 1.1.3 && ≤ 2.0.7
range

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

  2. Fix

    Update org.jenkins-ci.plugins:saml to 2.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21678 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.

Frequently Asked Questions

An extension point in Jenkins allows selectively disabling cross-site request forgery (CSRF) protection for specific URLs. SAML Plugin implements this extension point for the URL that users are redirected to after login. In Jenkins SAML Plugin 2.0.7 and earlier this implementation is too permissive, allowing attackers to craft URLs that would bypass the CSRF protection of any target URL.\n\nThis vulnerability was originally introduced in Jenkins SAML Plugin 1.1.3. Jenkins SAML Plugin 2.0.8 restricts which URLs it disables cross-site request forgery (CSRF) protection for to the one URL that n
O3 Security · Impact-Aware SCA

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