CVE-2025-31722 - Jenkins Templating Engine Plugin Security Vulnerability Allows Arbitrary Code Execution in Controller JVM

In this post, we dive deep into a discovered security vulnerability found in the Jenkins Templating Engine Plugin version 2.5.3 and earlier. Identified as CVE-2025-31722, this vulnerability opens up possibilities for attackers to execute arbitrary code within the context of the Jenkins controller JVM. The Jenkins Templating Engine Plugin typically simplifies and protracts the pipeline development process by enabling users to define libraries in folders.

However, it was noted that the libraries defined in these folders were not subject to sandbox protection. This oversight allows any attacker with the Item/Configure permission to execute arbitrary code on the Jenkins controller JVM. Consequently, this could result in severe damage, including unauthorized access to sensitive data or disruption of operations within the system.

To help you understand more about this vulnerability and clarify its implications, we have provided an in-depth analysis of the issue, including code snippets, links to original references, and a look at the exploit's details.

CVE-2025-31722: Overview

CVE-ID: CVE-2025-31722

Affected Software: Jenkins Templating Engine Plugin 2.5.3 and earlier

Exploit: Arbitrary code execution in the context of the Jenkins controller JVM

Permission: Requires attackers to have the Item/Configure permission

Code Snippet

The issue arises due to the lack of sandbox protection implementation in the plugin that specifically deals with libraries defined in folders. The following code snippet illustrates a typical example of how a library is currently being defined in a folder:

// library.groovy
void foo() {
    // Some function implementation here
}

void bar() {
    // Another function implementation here
}

// End of library.groovy

Now, when these libraries are loaded and used by the Jenkins Templating Engine Plugin, the plugin fails to apply sandbox protection, allowing a potential attacker with malicious intentions to execute arbitrary code as shown in the following example:

// Exploit.groovy
void foo() {
    // Arbitrary code execution
    Runtime.getRuntime().exec("some_malicious_command")
}

void bar() {
    // Another arbitrary code execution
    Runtime.getRuntime().exec("another_malicious_command")
}

// End of Exploit.groovy

Original References

This vulnerability was discovered and reported by a security researcher, who notified the Jenkins project team. The official references for the vulnerability and the affected plugin are presented below:

1. Jenkins Security Advisory - 2025-02-17
2. Jenkins Plugin Site - Templating Engine Plugin
3. CVE-2025-31722 - NVD Database

Exploit Details

The severity of this security vulnerability is relatively high, considering it allows attackers to execute arbitrary code on the Jenkins controller JVM as long as they have Item/Configure permission. This vulnerability can have several adverse implications for the affected Jenkins environment, including, but not limited to:

- Unauthorized access: Attackers can potentially gain unauthorized access to sensitive data or credentials, manipulate system configurations, or perform other malicious actions.
- Performance disruption: Faced with arbitrary code execution, the affected Jenkins environment might encounter performance disruptions or even a total loss of services if resource-hungry processes or malicious operations are executed.

Recommendations

In light of this security vulnerability, it's vital to protect your Jenkins environment by taking the following steps:

1. Update your Jenkins Templating Engine Plugin to version 2.5.4 or later at your earliest convenience. This version addresses the security issue by implementing sandbox protection correctly.
2. Regularly review user permissions within your Jenkins environment and ensure that only trusted users have access to the aforementioned critical permissions (Item/Configure, in this case).

By staying vigilant and keeping your Jenkins environment up-to-date, you can significantly mitigate the risks associated with security vulnerabilities like CVE-2025-31722 and protect your critical system assets.

Timeline

Published on: 04/02/2025 15:15:59 UTC
Last modified on: 04/29/2025 13:52:56 UTC