How severe is CVE-2021-21683?

CVE-2021-21683 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-21683?

CVE-2021-21683 affects the following packages: org.jenkins-ci.main:jenkins-core (Maven), org.jenkins-ci.main:jenkins-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-21683?

Update org.jenkins-ci.main:jenkins-core to 2.303.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21683 is resolved across your whole dependency graph.

How do I detect CVE-2021-21683 in my Maven dependencies?

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.

How do I mitigate CVE-2021-21683 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2021-21683 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21683 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21683?

CVE-2021-21683 has an EPSS (Exploit Prediction Scoring System) score of 2.2%, placing it in the 82th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-21683?

CVE-2021-21683 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-21683 published, and has it been updated?

CVE-2021-21683 was published on October 6, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2021-21683 — jenkins-core

MEDIUMFix: jenkinsci/jenkins@3f679fc

CVE-2021-21683 is a medium-severity (CVSS 6.5) Path Traversal 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.

Path traversal vulnerability on Windows in Jenkins

Also known asBIT-jenkins-2021-21683GHSA-4pw5-r58h-fv24

Published

Oct 6, 2021

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs82th percentile — riskier than 82% of all scored CVEsHighest risk

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

The file browser for workspaces, archived artifacts, and userContent/ in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier may interpret some paths to files as absolute on Windows.

This results in a path traversal vulnerability allowing attackers with Overall/Read permission (Windows controller) or Job/Workspace permission (Windows agents) to obtain the contents of arbitrary files.\n\nThe file browser in Jenkins 2.315, LTS 2.303.2 refuses to serve files that would be considered absolute paths.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jenkins-ci.main:jenkins-core`	all versions	2.303.2`org.jenkins-ci.main:jenkins-core:2.303.2`
☕Maven	`org.jenkins-ci.main:jenkins-core`	≥ 2.304&&< 2.315	2.315`org.jenkins-ci.main:jenkins-core:2.315`

Affected Products

1 product · 2 configurations

Application

jenkinsjenkins

≤ 2.314

range

Detection & mitigation playbook

Open-source dependency

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.
Fix
Update org.jenkins-ci.main:jenkins-core to 2.303.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21683 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

The file browser for workspaces, archived artifacts, and `userContent/` in Jenkins 2.314 and earlier, LTS 2.303.1 and earlier may interpret some paths to files as absolute on Windows. This results in a path traversal vulnerability allowing attackers with Overall/Read permission (Windows controller) or Job/Workspace permission (Windows agents) to obtain the contents of arbitrary files.\n\nThe file browser in Jenkins 2.315, LTS 2.303.2 refuses to serve files that would be considered absolute paths.

O3 Security · Impact-Aware SCA

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CVSS Score

6.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CWE Classification

CWE-22Path Traversal

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

jenkins

6.4/10

Code-Review6/10

Maintained10/10

Branch-Protection3/10

Assessed Oct 26, 2026

Timeline

Disclosed

Oct 6, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2021-21683

GHSA-4pw5-r58h-fv24

BIT-jenkins-2021-21683

References

Advisoryopenwall.com Advisoryjenkins.io · 2021 10 06 Advisorynvd.nist.gov · CVE 2021 21683 Webgithub.com · 3f679fc12d073676a4441d3fa8b5fff34c07662f Packagegithub.com · jenkins

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting jenkins-core are rated as high or higher (top: high).

CVE-2026-53436CVE-2026-53437CVE-2026-53440CVE-2026-53441CVE-2026-53439CVE-2026-53435CVE-2026-53442CVE-2026-53438

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026

CVE-2021-21683 — jenkins-core

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2021-21683 in your dependencies?