GHSA-vpjm-58cw-r8q5 BIT-jenkins-2021-21602 CVE-2021-21602
Arbitrary file read vulnerability in workspace browsers in Jenkins
- Severity
- 6.5 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 2.25%
- Chance of exploitation in the next 30 days. Higher than 82.93% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-59 Improper Link Resolution Before File Access ('Link Following')
- Fix
2.263.2- Upgrade org.jenkins-ci.main:jenkins-core to this version or later
Description
The file browser for workspaces, archived artifacts, and $JENKINS_HOME/userContent/ follows symbolic links to locations outside the directory being browsed in Jenkins 2.274 and earlier, LTS 2.263.1 and earlier.
This allows attackers with Job/Workspace permission and the ability to control workspace contents (e.g., with Job/Configure permission or the ability to change SCM contents) to create symbolic links that allow them to access files outside workspaces using the workspace browser.
This issue is caused by an incomplete fix for SECURITY-904 / CVE-2018-1000862 in the 2018-12-08 security advisory.
Jenkins 2.275, LTS 2.263.2 no longer supports symlinks in workspace browsers. While they may still exist on the file system, they are no longer shown on the UI, accessible via URLs, or included in directory content downloads.
This fix only changes the behavior of the Jenkins UI. Archiving artifacts still behaves as before.
Affected versions
Maven
| Package | Vulnerable | Fixed in |
|---|---|---|
| org.jenkins-ci.main:jenkins-core | < 2.263.2 |
2.263.2 |
| org.jenkins-ci.main:jenkins-core | >= 2.264, < 2.275 |
2.275 |
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 → 2.263.2
- maven
<dependency><groupId>org.jenkins-ci.main</groupId><artifactId>jenkins-core</artifactId><version>2.263.2</version></dependency>- gradle
implementation("org.jenkins-ci.main:jenkins-core:2.263.2")
Severity breakdown
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
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.
References
Advisories
Packages
Other links
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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