CVE-2022-43420 is a stored cross-site scripting (XSS) vulnerability identified in the Jenkins Contrast Continuous Application Security Plugin version 3.9 and earlier. This plugin integrates Contrast Security's application security capabilities into Jenkins, a widely used automation server for continuous integration and continuous delivery (CI/CD). The vulnerability arises because the plugin does not properly escape data returned from the Contrast service when generating reports. Specifically, if an attacker can control or modify the API responses from the Contrast service, they can inject malicious scripts that are stored and later executed in the context of the Jenkins web interface when a user views the generated report. This stored XSS vulnerability is classified under CWE-79, which involves improper neutralization of input during web page generation. The CVSS v3.1 base score is 5.4 (medium severity), with an attack vector of network (remote exploitation), low attack complexity, requiring privileges (PR:L) and user interaction (UI:R). The scope is changed (S:C), indicating that the vulnerability affects components beyond the initially vulnerable component. The impact affects confidentiality and integrity to a limited extent but does not affect availability. No known exploits in the wild have been reported, and no official patches are linked in the provided information. The vulnerability requires that an attacker have the ability to control or modify Contrast service API responses, which implies some level of access or compromise of the Contrast service or its communication channel with Jenkins. When exploited, the attacker could execute arbitrary scripts in the Jenkins UI, potentially leading to session hijacking, credential theft, or further compromise of the Jenkins environment.

For European organizations using Jenkins with the Contrast Continuous Application Security Plugin, this vulnerability poses a moderate risk. Jenkins is widely used in software development pipelines across Europe, especially in sectors with heavy software development such as finance, telecommunications, and government. Exploitation could allow attackers to execute malicious scripts in the Jenkins interface, potentially leading to unauthorized access to sensitive build information, credentials, or pipeline configurations. This could compromise the integrity of the software supply chain, leading to insertion of malicious code or disruption of development workflows. Given the plugin’s role in security reporting, a successful attack could also undermine trust in security assessments, delaying detection of other vulnerabilities. The requirement for attacker control over Contrast API responses limits the attack surface but does not eliminate risk, especially if Contrast service communications are not adequately secured or if an insider threat exists. The medium severity rating reflects a balance between the potential impact and the exploitation complexity. Organizations with high compliance requirements under GDPR and other European data protection laws must consider the confidentiality implications of such an attack, as leakage of personal or sensitive data through Jenkins could lead to regulatory penalties.

To mitigate this vulnerability, European organizations should first verify if they are using the Jenkins Contrast Continuous Application Security Plugin version 3.9 or earlier. Immediate steps include: 1) Restrict and monitor access to the Contrast service API to prevent unauthorized modification of API responses. This includes enforcing strong authentication, network segmentation, and encryption of API communications (e.g., TLS). 2) Implement Content Security Policy (CSP) headers in Jenkins to reduce the impact of XSS by restricting the execution of unauthorized scripts. 3) Regularly audit Jenkins plugin versions and update to the latest versions once a patch is released by the vendor. In the absence of an official patch, consider disabling the plugin temporarily if it is not critical to operations. 4) Harden Jenkins access controls, including multi-factor authentication and role-based access control, to limit the potential damage from compromised sessions. 5) Monitor Jenkins logs and network traffic for unusual activity that could indicate exploitation attempts. 6) Educate developers and DevOps teams about the risks of XSS and the importance of securing CI/CD pipelines. 7) If possible, validate and sanitize all data received from external services before rendering in Jenkins reports, either through custom scripting or additional security plugins.