CVE-2025-3841 in jam
Summary
by MITRE • 04/21/2025
A vulnerability, which was classified as problematic, was found in wix-incubator jam up to e87a6fd85cf8fb5ff37b62b2d68f917219d07ae9. This affects an unknown part of the file jam.py of the component Jinja2 Template Handler. The manipulation of the argument config['template'] leads to improper neutralization of special elements used in a template engine. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used. This product takes the approach of rolling releases to provide continious delivery. Therefore, version details for affected and updated releases are not available.
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Analysis
by VulDB Data Team • 06/23/2025
CVE-2025-3841 represents a critical server-side template injection vulnerability within the wix-incubator jam application, specifically affecting the Jinja2 Template Handler component. This vulnerability stems from inadequate input validation and sanitization of the config['template'] parameter within the jam.py file, creating a pathway for malicious actors to manipulate template rendering processes. The flaw falls under CWE-74, Improper Neutralization of Special Elements in Template Engines, which is a well-documented weakness in application security where user-supplied data is not properly escaped or filtered before being processed by template engines. The vulnerability is particularly concerning because it allows local privilege escalation attacks that can be executed directly on the host system, eliminating the need for network-based exploitation. The exploit has been publicly disclosed and is actively being used in the wild, indicating that threat actors have already developed working attack vectors against this weakness. The rolling release methodology employed by the wix-incubator jam project complicates remediation efforts as the exact version ranges affected and the corresponding patches are not clearly documented, making it difficult for security teams to determine their vulnerability status and implement appropriate fixes. The attack surface is further expanded by the fact that this is a template engine vulnerability, meaning that an attacker could potentially execute arbitrary code on the server, access sensitive data, or compromise the entire host environment.
The operational impact of CVE-2025-3841 extends beyond simple code execution to encompass full system compromise capabilities, as demonstrated by the ATT&CK framework's T1059.001 technique for Command and Scripting Interpreter. When an attacker successfully exploits this vulnerability, they can leverage the Jinja2 template engine's capabilities to inject malicious code that executes with the privileges of the jam application process. This creates opportunities for lateral movement within the network, data exfiltration, and persistence mechanisms that could be established through the compromised template handler. The vulnerability's classification as local attack vector means that attackers do not require external network access to exploit it, significantly increasing the risk to systems where the application is running with elevated privileges. Organizations using this software are particularly vulnerable because the exploit can be used to gain unauthorized access to sensitive configuration files, user data, and system resources that the jam application may have access to. The lack of version information in the release notes makes it challenging for security teams to perform accurate risk assessment and prioritization of remediation efforts.
Mitigation strategies for CVE-2025-3841 must address both immediate remediation and long-term security posture improvements. Organizations should implement strict input validation and sanitization for all user-supplied template parameters, particularly focusing on the config['template'] argument within the jam.py component. The principle of least privilege should be enforced by running the jam application with minimal required permissions, limiting the potential impact of successful exploitation. Security teams should also consider implementing web application firewalls and content filtering mechanisms that can detect and block malicious template injection attempts. The ATT&CK framework's T1190 technique for Exploit Public-Facing Application provides guidance for defending against this type of vulnerability through proper input validation and secure coding practices. Regular security audits and penetration testing should be conducted to identify similar weaknesses in other components that may utilize template engines. Additionally, organizations should establish a more robust versioning and release documentation process to ensure that vulnerability information is properly tracked and communicated to users. The rolling release model, while beneficial for continuous delivery, creates security challenges that require more proactive vulnerability management and communication strategies. Implementing automated vulnerability scanning tools that can detect template injection patterns and maintaining up-to-date threat intelligence feeds will help organizations stay ahead of evolving attack vectors targeting similar weaknesses in template processing components.