CVE-2021-21659: XXE vulnerability in Jenkins URLTrigger Plugin
Summary
CVE-2021-21659: XXE vulnerability in Jenkins URLTrigger Plugin. Affects org.jenkins-ci.plugins:urltrigger versions < 0.49. Fixed in 0.49. How to fix ↓
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Background
The Jenkins URLTrigger Plugin is a Maven package that allows users to trigger Jenkins jobs based on changes to the content of an URL. It provides functionality for monitoring XML documents and initiating job builds when specific changes occur. The plugin is widely used in Jenkins environments for automating build and deployment processes.
Vulnerability Detail
The URLTrigger Plugin version 0.48 and earlier is vulnerable to an XML External Entity (XXE) attack. The plugin does not properly configure its XML parser, enabling attackers with Job/Configure permission or control over the contents of a URL to exploit the vulnerability. By crafting a malicious XML document, an attacker can extract sensitive information, perform server-side request forgery, or launch denial-of-service attacks against the Jenkins controller or agent. The vulnerability has a CVSS score of 7.1, indicating a high severity level.
How To Fix
Latest published version: 1.06 as of 23 Oct 2026
Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
0.49
This is the first release that contains the fix.
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Workaround
There is no specific workaround mentioned for this vulnerability. However, users can consider temporarily disabling or removing the URLTrigger Plugin if it is not essential for their Jenkins environment until the plugin can be updated to the fixed version.
Conclusion
The XXE vulnerability in the Jenkins URLTrigger Plugin (CVE-2021-21659) poses a significant risk to Jenkins environments. It allows attackers to exploit the plugin's XML parser and potentially extract sensitive information, perform server-side request forgery, or launch denial-of-service attacks. To mitigate this vulnerability, it is crucial to update the URLTrigger Plugin to version 0.49 or later. For further assistance or support in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for org.jenkins-ci.plugins:urltrigger →
FAQ
An XML External Entity (XXE) vulnerability is a type of attack that exploits the processing of XML input by an application. It allows an attacker to include external entities or files, leading to various security risks such as information disclosure, server-side request forgery, or denial-of-service attacks.
The XXE vulnerability in the URLTrigger Plugin can enable an attacker to extract sensitive information from the Jenkins controller or agent, perform server-side request forgery to access internal resources, or launch denial-of-service attacks that disrupt the Jenkins environment.
Users of Jenkins who have installed and are using the URLTrigger Plugin version 0.48 or earlier are affected by this vulnerability. Specifically, attackers with Job/Configure permission or control over the contents of a URL being examined for changes can exploit the vulnerability.
Yes, the vulnerability can be fixed by updating the URLTrigger Plugin to version 0.49 or later. The updated version disables external entity resolution for its XML parser, effectively mitigating the XXE vulnerability.
To update the URLTrigger Plugin in Jenkins, follow these steps:
- Log in to your Jenkins instance as an administrator.
- Go to the 'Manage Jenkins' page.
- Click on 'Manage Plugins'.
- In the 'Available' tab, search for 'URLTrigger Plugin'.
- Check the box next to the plugin and click 'Install without restart'.
- Once the installation is complete, restart Jenkins to apply the changes.
Related vulnerabilities
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