CVE-2025-14046 is a cross-site scripting (XSS) vulnerability classified under CWE-79 that affects GitHub Enterprise Server versions prior to 3.18.3, 3.17.9, 3.16.12, 3.15.16, and 3.14.21. The vulnerability stems from improper neutralization of user-supplied HTML input during web page generation, specifically allowing injection of DOM elements with IDs that collide with server-initialized data islands. These collisions cause overwriting or shadowing of critical application state objects used in certain Project views. As a result, attackers can manipulate the client-side DOM to trigger unintended server-side POST requests or unauthorized backend interactions. Exploitation requires the attacker to have access to the targeted GitHub Enterprise Server instance and to lure a privileged user into viewing maliciously crafted content containing conflicting HTML elements. The vulnerability does not require authentication or elevated privileges for the attacker but does require user interaction (viewing the malicious content). The CVSS 4.0 vector indicates network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality and integrity. No known exploits have been reported in the wild as of the publication date, but the potential impact on sensitive project data and workflows is significant. The vulnerability affects multiple major versions of GitHub Enterprise Server, a widely used platform for source code management and collaboration in enterprise environments.

For European organizations, the impact of CVE-2025-14046 can be substantial due to the widespread adoption of GitHub Enterprise Server in software development and DevOps workflows. Successful exploitation could lead to unauthorized modification or disclosure of sensitive project data, manipulation of project states, and potentially unauthorized backend operations that compromise the integrity and confidentiality of code repositories and related assets. This could disrupt development processes, introduce malicious code, or leak proprietary information. Given that privileged users must be tricked into viewing malicious content, targeted phishing or social engineering campaigns could be employed by attackers. The vulnerability's ability to cause server-side POST requests without proper authorization increases the risk of lateral movement or privilege escalation within the enterprise environment. The absence of known exploits in the wild provides a window for proactive mitigation, but organizations should act swiftly to prevent potential exploitation, especially those in regulated industries or with critical software supply chains in Europe.

European organizations should immediately upgrade GitHub Enterprise Server to versions 3.18.3, 3.17.9, 3.16.12, 3.15.16, or 3.14.21 or later, where the vulnerability is patched. Until patching is complete, implement strict content security policies (CSP) to restrict the execution of untrusted scripts and reduce the risk of XSS exploitation. Employ web application firewalls (WAFs) with custom rules to detect and block malicious payloads targeting this vulnerability. Enhance user awareness training focused on recognizing phishing and social engineering attempts that could deliver malicious content. Restrict access to GitHub Enterprise Server instances to trusted networks and users, minimizing exposure to untrusted actors. Monitor server logs and user activity for unusual POST requests or backend interactions that could indicate exploitation attempts. Consider deploying runtime application self-protection (RASP) solutions to detect and block anomalous DOM manipulations. Finally, review and harden project view configurations to limit the impact of DOM element collisions where feasible.