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MEDIUM severity

CVE-2021-21682 — jenkins-core

MEDIUMFix: jenkinsci/jenkins@c2c2b59

CVE-2021-21682 is a medium-severity (CVSS 4.3) vulnerability in org.jenkins-ci.main:jenkins-core. A fix is available for org.jenkins-ci.main:jenkins-core — see the affected versions and patch details below.

Improper handling of equivalent directory names on Windows in Jenkins

Also known asBIT-jenkins-2021-21682GHSA-6q4g-84f3-mw74
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk
0.00%0.50%1.00%1.50%0.2%1.0%May 26Aug 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

2 pkgs affected
☕org.jenkins-ci.main:jenkins-core☕org.jenkins-ci.main:jenkins-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

Jenkins stores jobs and other entities on disk using their name shown on the UI as file and folder names.

On Windows, when specifying a file or folder with a trailing dot character (example.), the file or folder will be treated as if that character was not present (example). As both are legal names for jobs and other entities in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier, this could allow users with the appropriate permissions to change or replace configurations of jobs and other entities.

Jenkins 2.315, LTS 2.303.2 does not allow names of jobs and other entities to end with a dot character.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.jenkins-ci.main:jenkins-core≥ 2.304&&< 2.3152.315org.jenkins-ci.main:jenkins-core:2.315
☕Mavenorg.jenkins-ci.main:jenkins-coreall versions2.303.2org.jenkins-ci.main:jenkins-core:2.303.2

Affected Products

1 product · 2 configurations
Application
jenkinsjenkins
≤ 2.314
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.main:jenkins-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.jenkins-ci.main:jenkins-core to 2.315 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21682 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

Jenkins stores jobs and other entities on disk using their name shown on the UI as file and folder names. On Windows, when specifying a file or folder with a trailing dot character (`example.`), the file or folder will be treated as if that character was not present (`example`). As both are legal names for jobs and other entities in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier, this could allow users with the appropriate permissions to change or replace configurations of jobs and other entities. Jenkins 2.315, LTS 2.303.2 does not allow names of jobs and other entities to end with a do
O3 Security · Impact-Aware SCA

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CVE-2021-21682: jenkins-core — Fixed in 2.315