CVE-2023-2015 in Community Edition
Summary
by MITRE • 06/07/2023
An issue has been discovered in GitLab CE/EE affecting all versions starting from 15.8 before 15.10.8, all versions starting from 15.11 before 15.11.7, all versions starting from 16.0 before 16.0.2. A reflected XSS was possible when creating new abuse reports which allows attackers to perform arbitrary actions on behalf of victims.
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Analysis
by VulDB Data Team • 12/17/2025
This vulnerability represents a critical reflected cross-site scripting flaw in GitLab Community and Enterprise Edition products that emerged in version 15.8 and persisted through specific unpatched releases. The issue specifically affects the abuse report creation functionality, where malicious actors could inject malicious scripts into the application's response that would execute in the context of a victim's browser session. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is a fundamental web application security weakness that allows attackers to inject client-side scripts into web pages viewed by other users. The flaw enables attackers to perform arbitrary actions on behalf of victims, potentially leading to session hijacking, privilege escalation, or data exfiltration.
The technical implementation of this vulnerability occurs when GitLab processes abuse report submissions without proper input sanitization or output encoding of user-supplied data. When users create abuse reports, the application fails to adequately validate and escape special characters in the submitted content, allowing attackers to inject malicious JavaScript code. The reflected nature of this vulnerability means that the malicious script is reflected back to the user through the application's response, typically via URL parameters or form fields, without being stored on the server. This makes exploitation straightforward as attackers can simply craft malicious URLs or forms that, when clicked by a victim, execute the injected code in the victim's browser context.
The operational impact of this vulnerability is significant for organizations using affected GitLab versions, as it creates a persistent attack vector that can be exploited by adversaries to compromise user sessions and potentially gain unauthorized access to sensitive repositories, code, and project data. Attackers could leverage this vulnerability to steal session cookies, modify project configurations, or even execute arbitrary code on behalf of authenticated users. The vulnerability particularly affects developers and administrators who might inadvertently click on malicious links within abuse reports or project discussions, making it a high-risk issue for organizations that rely heavily on GitLab for code management and collaboration. The attack surface is broad since abuse reports can be created by any user with appropriate permissions, and the reflected nature of the vulnerability means that even casual browsing of affected pages could trigger exploitation.
Organizations should immediately upgrade to the patched versions 15.10.8, 15.11.7, or 16.0.2 to remediate this vulnerability. The mitigation strategy should also include implementing additional security measures such as web application firewalls, input validation, and output encoding controls to prevent similar issues in other parts of the application. Security teams should conduct thorough audits of all user input handling mechanisms and implement proper content security policies to prevent script execution in user-facing contexts. This vulnerability highlights the importance of proper input sanitization and output encoding in web applications, aligning with ATT&CK technique T1213.002 for Data from Information Repositories, where attackers could potentially extract sensitive information through session manipulation or privilege escalation. Organizations should also consider implementing security awareness training for developers to prevent similar issues in custom applications and ensure proper secure coding practices are followed throughout the software development lifecycle.