CVE-2024-3092 in Community Edition
Summary
by MITRE • 04/12/2024
An issue has been discovered in GitLab CE/EE affecting all versions starting from 16.9 before 16.9.4, all versions starting from 16.10 before 16.10.2. A payload may lead to a Stored XSS while using the diff viewer, allowing attackers to perform arbitrary actions on behalf of victims.
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Analysis
by VulDB Data Team • 04/06/2025
This vulnerability exists in GitLab Community Edition and Enterprise Edition products, specifically impacting versions from 16.9.0 through 16.9.3 and 16.10.0 through 16.10.1. The flaw resides in the diff viewer functionality which processes and displays code changes between different versions of files within the GitLab interface. When users view diff outputs containing specially crafted malicious payloads, the system fails to properly sanitize user input before rendering it in the browser context. This represents a classic stored cross-site scripting vulnerability where malicious code can be permanently stored within the GitLab system and subsequently executed whenever victims view affected diff pages. The vulnerability stems from insufficient input validation and output encoding mechanisms in the diff rendering component.
The technical exploitation of this vulnerability requires an attacker to first gain access to a GitLab instance and upload or commit malicious content that contains XSS payloads within the diff output. Once committed, any user who views the affected diff page will execute the malicious script within their browser context, potentially leading to session hijacking, privilege escalation, or data exfiltration. The stored nature of this vulnerability means that the malicious payload persists even after the initial commit, making it particularly dangerous as it can affect multiple users over time. This flaw directly maps to CWE-79 which defines cross-site scripting vulnerabilities where insufficient validation of input data allows attackers to inject malicious scripts into web applications. The vulnerability also aligns with ATT&CK technique T1531 which involves using malicious code to gain access to systems, specifically through web-based attack vectors.
The operational impact of this vulnerability extends beyond simple data theft or session manipulation. Attackers could potentially escalate privileges within the GitLab environment, access sensitive project information, or use the compromised user sessions to perform actions such as creating new repositories, modifying code, or accessing confidential data. The vulnerability affects all users who have access to the diff viewer functionality, which is a core component of GitLab's code review and collaboration features. Organizations using GitLab in production environments face significant risk as this vulnerability could be exploited by both internal and external attackers who gain access to the system through other means. The persistence of the stored XSS makes this vulnerability particularly concerning for environments where code review and diff viewing are frequently accessed by multiple team members.
Mitigation strategies should include immediate patching of affected GitLab installations to versions 16.9.4 or 16.10.2 and later. Organizations should also implement additional defensive measures such as input validation at the application level, regular security scanning of committed code, and monitoring for unusual diff activity. Network-based protections like web application firewalls can provide additional layers of defense, though they may not prevent all variants of this attack. Administrators should consider implementing stricter access controls and monitoring user activities related to code commits and diff viewing. The vulnerability highlights the importance of proper input sanitization and output encoding practices in web applications, particularly in collaborative environments where user-generated content is displayed. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in other components of the GitLab platform and related systems.