CVE-2025-52876 in TeamCity
Summary
by MITRE • 06/23/2025
In JetBrains TeamCity before 2025.03.3 reflected XSS on the favoriteIcon page was possible
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Analysis
by VulDB Data Team • 06/26/2025
The vulnerability identified as CVE-2025-52876 represents a reflected cross-site scripting flaw discovered in JetBrains TeamCity prior to version 2025.03.3. This security weakness specifically affects the favoriteIcon page functionality within the TeamCity continuous integration and deployment platform. The issue arises when user-supplied input containing malicious script code is reflected back to the browser without proper sanitization or encoding, creating an avenue for attackers to execute arbitrary JavaScript in the context of authenticated users' browsers. Such vulnerabilities are particularly dangerous in development environments where TeamCity serves as a central hub for software development workflows and typically requires elevated privileges to access.
The technical exploitation of this reflected XSS vulnerability occurs when an attacker crafts a malicious URL containing script payloads and convinces a victim to click on the link while authenticated to the TeamCity instance. The application fails to properly sanitize input parameters passed to the favoriteIcon page, allowing the malicious code to execute in the victim's browser session. This type of vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws where untrusted data is directly included in web pages without proper validation or encoding. The attack vector leverages the principle that user-provided data should never be trusted and must be properly escaped or encoded before being rendered in web contexts.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to hijack user sessions, steal sensitive credentials, access restricted project information, or manipulate build configurations through the authenticated user's privileges. In enterprise environments where TeamCity manages critical CI/CD pipelines, this vulnerability could allow adversaries to disrupt development processes, inject malicious code into builds, or gain unauthorized access to source code repositories. The reflected nature of the vulnerability means that the attack requires user interaction through a crafted link, but the ease of exploitation and the potential for privilege escalation make this a significant concern for organizations relying on TeamCity for their software delivery processes.
Organizations should immediately upgrade to JetBrains TeamCity version 2025.03.3 or later to remediate this vulnerability, as the fix likely includes proper input sanitization and output encoding mechanisms for the favoriteIcon page functionality. Additional mitigations include implementing proper content security policies to restrict script execution, conducting regular security assessments of web applications, and establishing secure coding practices that enforce input validation and output encoding. From an ATT&CK framework perspective, this vulnerability maps to techniques involving client-side code injection and session hijacking, with potential for privilege escalation through the exploitation of authenticated web interfaces. Security teams should also consider implementing web application firewalls and monitoring for suspicious user behavior patterns that might indicate exploitation attempts.