Recently, a new vulnerability, CVE-2025-0555, has been discovered and found to affect all versions of GitLab-EE ranging from 16.6 to the one before 17.7.6, as well as 17.8 prior to 17.8.4, and 17.9 prior to 17.9.1. This vulnerability is a Cross-Site Scripting (XSS) issue that allows attackers to bypass security settings and execute arbitrary scripts in a user's browser under specific circumstances. In this post, we will discuss the details of this vulnerability, code snippets and links to the original references.
Background
Cross-Site Scripting, or XSS, is a common cybersecurity vulnerability that allows an attacker to inject malicious scripts into web pages viewed by other users. This can lead to a range of attacks, including session hijacking, information theft, and potentially even remote code execution on the victim's machine.
In the case of CVE-2025-0555, the vulnerability lies within GitLab-EE, an enterprise-class Git repository management system. GitLab-EE is widely used by businesses and organizations for source code management, continuous integration and deployment (CI/CD) workflows, and other development processes.
Exploit Details
The XSS vulnerability in GitLab-EE is a result of improper input validation in the handling of user-submitted content, such as comments, issues, or merge request descriptions. Once an attacker is able to successfully exploit the vulnerability, they can execute arbitrary scripts in the victim's browser, which may lead to sensitive information disclosure, account takeover, or other malicious activities.
To exploit the vulnerability, an attacker would need to craft a specially crafted payload containing their malicious script and inject it into an affected version of GitLab-EE. Here's a simple code snippet demonstrating how an attacker might craft a basic XSS payload:
<script>
alert('XSS Vulnerability - CVE-2025-0555');
</script>
This payload, when injected into GitLab-EE using one of the vulnerable fields, would trigger a JavaScript alert() message to appear in the victim's browser.
However, it is important to note that this vulnerability is exploitable only under specific conditions. To exploit the vulnerability, the attacker must have legitimate access to the affected GitLab-EE instance, and they must also be able to coerce the target user into viewing the malicious content.
Original References
GitLab has acknowledged the vulnerability and provided patches for the affected versions. Users are advised to upgrade to the following patched versions to mitigate the risk:
- GitLab-EE 17.7.6: GitLab Release Notes
- GitLab-EE 17.8.4: GitLab Release Notes
- GitLab-EE 17.9.1: GitLab Release Notes
Information about the vulnerability can also be found in GitLab's official security advisory
Upgrade to the latest patched version of GitLab-EE in order to address the vulnerability.
2. Regularly review user accounts and permissions within your GitLab-EE instance to ensure that only authorized users have access.
3. Continuously educate users about cybersecurity risks and best practices, advising them not to click on suspicious links or interact with unfamiliar content.
Conclusion
XSS risks remain one of the most prevalent web security vulnerabilities. The CVE-2025-0555 case serves as a reminder that even widely trusted software systems like GitLab-EE can be susceptible to these threats. It is crucial for teams managing development infrastructure to stay informed about vulnerabilities and apply the appropriate patches as soon as possible in order to minimize potential risk.
Timeline
Published on: 03/03/2025 16:15:39 UTC
Last modified on: 03/07/2025 19:37:57 UTC