CVE-2021-21682Network attack vector

Authenticated job overwrite via trailing-dot name collision

Published Oct 6, 2021 · Updated Aug 3, 2024

Path equivalence in Jenkins 2.314 and earlier and LTS 2.303.1 and earlier allows remote authenticated users to replace job data on Windows. Jenkins uses UI entity names as on-disk file and folder names, but accepts a trailing dot that Windows resolves to the same path as the name without it. The attacker needs permission to create or rename the affected entity; a collision can change or replace its configuration and stored data.

CVSS severity4.3
Medium
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path equivalence in Jenkins 2.314 and earlier and LTS 2.303.1 and earlier allows remote authenticated users to replace job data on Windows. Jenkins uses UI entity names as on-disk file and folder names, but accepts a trailing dot that Windows resolves to the same path as the name without it. The attacker needs permission to create or rename the affected entity; a collision can change or replace its configuration and stored data.

The record

CVE
CVE-2021-21682
Published
Oct 6, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
Jenkins
Classifications
CWE-42, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=2.314
  2. Affected versionversion=unspecified <=LTS 2.303.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jenkins Project · Jenkinsversion=unspecified <=2.314; version=unspecified <=LTS 2.303.1

Published CVSS scores

6.3GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-42Path Equivalence: 'filename.' (Trailing Dot)
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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