CVE-2025-3841 is a medium-severity vulnerability identified in the wix-incubator jam project, specifically affecting the Jinja2 Template Handler component within the jam.py file. The vulnerability arises from improper neutralization of special elements used in the template engine, triggered by manipulation of the argument config['template']. This improper neutralization can lead to injection of malicious template code, potentially allowing an attacker to execute arbitrary code or manipulate the template rendering process. The vulnerability is exploitable locally, meaning an attacker must have access to the host where the vulnerable jam instance is running. The product uses a rolling release model, which complicates pinpointing exact affected or patched versions, but the vulnerability is confirmed in version e87a6fd85cf8fb5ff37b62b2d68f917219d07ae9. While no public exploits have been observed in the wild, the vulnerability has been publicly disclosed, increasing the risk of exploitation attempts. The root cause is incomplete filtering or sanitization of special template elements, which are critical in template engines like Jinja2 to prevent injection attacks. Given the nature of template injection vulnerabilities, successful exploitation could lead to unauthorized code execution, data leakage, or compromise of application integrity depending on the context of the jam deployment and its privileges.

For European organizations using wix-incubator jam, particularly those integrating Jinja2 templates for dynamic content generation, this vulnerability poses a risk of local privilege escalation or unauthorized code execution. If jam is deployed in environments where multiple users have local access or where the application processes untrusted input for template rendering, attackers could leverage this flaw to execute arbitrary code, potentially leading to data breaches, service disruption, or further lateral movement within the network. The impact is heightened in sectors with sensitive data such as finance, healthcare, or critical infrastructure, where integrity and confidentiality of data are paramount. Additionally, organizations relying on continuous deployment pipelines using jam could face supply chain risks if compromised templates propagate malicious code. Although exploitation requires local access, insider threats or compromised user accounts could facilitate attacks. The lack of clear patch versions and rolling release nature may delay remediation, increasing exposure time.

1. Immediate review and sanitization of all inputs passed to the config['template'] parameter to ensure no untrusted data can influence template rendering. 2. Implement strict input validation and escaping mechanisms specifically tailored for Jinja2 template syntax to prevent injection of special elements. 3. Restrict local access to hosts running wix-incubator jam to trusted users only, employing strong access controls and monitoring for suspicious activity. 4. Employ application-level sandboxing or containerization to limit the impact of potential code execution resulting from template injection. 5. Monitor for updates from wix-incubator jam project closely and apply patches as soon as they become available, despite the rolling release model. 6. Conduct code audits focusing on template handling logic to identify and remediate similar injection risks. 7. Use runtime application self-protection (RASP) tools or web application firewalls (WAF) configured to detect anomalous template engine behavior. 8. Educate developers and DevOps teams about secure template usage patterns and the risks of improper neutralization of template elements.