GHSA-r6qv-frpc-q66c BIT-jenkins-2026-33001 CVE-2026-33001
Jenkins has a link following vulnerability allows arbitrary file creation
- Severity
- 8.8 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 2.07%
- Chance of exploitation in the next 30 days. Higher than 81.40% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-59 Improper Link Resolution Before File Access ('Link Following')
- CWE-61 UNIX Symbolic Link (Symlink) Following
- Fix
2.555- Upgrade org.jenkins-ci.main:jenkins-core to this version or later
Description
Jenkins 2.554 and earlier, LTS 2.541.2 and earlier does not safely handle symbolic links during the extraction of .tar and .tar.gz archives, allowing crafted archives to write files to arbitrary locations on the filesystem, restricted only by file system access permissions of the user running Jenkins. This can be exploited to deploy malicious scripts or plugins on the controller by attackers with Item/Configure permission, or able to control agent processes.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.jenkins-ci.main:jenkins-core | < 2.555 |
2.555 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
org.jenkins-ci.main:jenkins-core Maven → 2.555
- maven
<dependency><groupId>org.jenkins-ci.main</groupId><artifactId>jenkins-core</artifactId><version>2.555</version></dependency>- gradle
implementation("org.jenkins-ci.main:jenkins-core:2.555")
Severity breakdown
CVSS 3.1 8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-59: Improper Link Resolution Before File Access ('Link Following')
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How to prevent it
- Architecture and Design: Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
CWE-61: UNIX Symbolic Link (Symlink) Following
The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.
How to prevent it
- Implementation: Symbolic link attacks often occur when a program creates a tmp directory that stores files/links. Access to the directory should be restricted to the program as to prevent attackers from manipulating the files.
- Architecture and Design: Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
References
Advisories
Packages
Other links
- github.com/jenkinsci/jenkins/commit/6dc99937605d5bddfeaae43a4cd14c2571e23adc
- github.com/jenkinsci/jenkins/releases/tag/jenkins-2.555
- jenkins.io/security/advisory/2026-03-18
- access.redhat.com/errata/RHSA-2026:10199
- access.redhat.com/errata/RHSA-2026:10201
- access.redhat.com/errata/RHSA-2026:10204
- access.redhat.com/errata/RHSA-2026:10205
- access.redhat.com/errata/RHSA-2026:10206
- access.redhat.com/errata/RHSA-2026:10209
- access.redhat.com/errata/RHSA-2026:10211
- access.redhat.com/errata/RHSA-2026:10213
- access.redhat.com/errata/RHSA-2026:10214
- access.redhat.com/errata/RHSA-2026:10215
- access.redhat.com/security/cve/CVE-2026-33001
- bugzilla.redhat.com/show_bug.cgi
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33001.json
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-6f9g-cxwr-q5jr Arbitrary file read vulnerability through the Jenkins CLI can lead to RCE | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-8pqx-3rxx-f5pm Jenkins discloses project names via fingerprints | High Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-26wc-3wqp-g3rp Deserialization of Untrusted Data in Jenkins | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| CVE-2018-1000861 Deserialization of Untrusted Data in Jenkins | Critical Known exploited | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-m6wv-wh8g-64xc Jenkins does not encrypt secrets from POST config.xml submissions before storing them in job configurations | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-93qh-vwrm-c5pw Jenkins: Stored XSS vulnerability in node offline cause description | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-92m7-4fpw-2wxm Jenkins: Open Redirect phishing attacks possible via "from" parameter in "Delegate to servlet container" | Medium | Also affects org.jenkins-ci.main:jenkins-core |
| GHSA-g28p-6mcc-v4rv Jenkins exposes other users' timezone and view names to users with Overall/Read permission | Medium | Also affects org.jenkins-ci.main:jenkins-core |
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