Description

Jenkins maintainers have released critical security updates to address multiple vulnerabilities affecting the platform, including high-severity flaws that could expose CI/CD pipelines to denial-of-service (DoS) and cross-site scripting (XSS) attacks. The most severe of these, CVE-2025-67635, impacts the HTTP-based Command Line Interface (CLI) in Jenkins versions 2.540 and earlier. This flaw allows unauthenticated attackers to flood the server with malformed connection requests, exhausting server resources and potentially causing a DoS. Another critical vulnerability, CVE-2025-67641, was discovered in the Coverage Plugin. This flaw lets attackers inject malicious JavaScript into coverage reports, leading to stored XSS attacks and potentially allowing session hijacking when administrators view the compromised reports. The plugin has been patched in version 2.3056.v1dfe888b-0249, which now validates result identifiers to prevent this exploit. Additionally, build authorization tokens were previously stored in plaintext (CVE-2025-67637), but the update now encrypts these tokens to enhance security. A medium-severity flaw, CVE-2025-67636, allowed users with View or Read permissions to view encrypted passwords, which has now been fixed by enforcing stricter permission checks. However, a still unresolved vulnerability in the HashiCorp Vault Plugin (CVE-2025-67642) lets unauthorized users access system-scoped credentials, and administrators are advised to monitor configurations until a patch is released. To mitigate these risks, Jenkins administrators should immediately upgrade to Jenkins Core 2.541 or LTS 2.528.3, update affected plugins (Git Client Plugin v6.4.1, BlazeMeter Plugin v4.27), and encrypt old build tokens. These actions will help protect Jenkins instances from the identified vulnerabilities and improve overall security.