CVE-2026-13320 in GitLab
Summary
by MITRE • 07/09/2026
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.7 before 18.11.7, 19.0 before 19.0.4, and 19.1 before 19.1.2 that under certain conditions could have allowed an authenticated user to execute arbitrary scripts in another user's browser session due to improper sanitization of user-supplied input.
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Analysis
by VulDB Data Team • 07/09/2026
This vulnerability represents a critical cross-site scripting flaw that enables authenticated users to inject malicious scripts into other users' browser sessions through improperly sanitized input handling within GitLab's web interface. The security issue affects multiple version ranges including 15.7 through 18.11.6, 19.0 through 19.0.3, and 19.1 through 19.1.1, demonstrating the widespread impact across GitLab's release cycles. The flaw falls under CWE-79 which specifically addresses cross-site scripting vulnerabilities where input validation and output encoding mechanisms fail to properly sanitize user-supplied data before rendering it in web pages.
The technical execution of this vulnerability occurs when authenticated users leverage the insufficient input sanitization to inject malicious JavaScript code into GitLab's user interface components. This allows attackers to execute arbitrary scripts within the context of other users' browser sessions, potentially enabling session hijacking, credential theft, or further exploitation of the compromised user's privileges. The attack vector typically involves manipulating form inputs, comments, or other user-controllable fields that are subsequently rendered without proper HTML escaping or content security policy enforcement.
Operational impact of this vulnerability extends beyond simple script execution as it fundamentally compromises the integrity of GitLab's session management and user isolation mechanisms. An attacker could leverage this flaw to access sensitive project information, manipulate code repositories, or escalate privileges within the platform. The authenticated nature of the attack means that exploitation requires a valid user account, but once achieved, the malicious scripts can persistently target other users who interact with the affected GitLab instance.
Mitigation strategies should focus on implementing robust input validation and output encoding mechanisms throughout the application's codebase, particularly in areas where user-generated content is rendered. Organizations should immediately upgrade to the patched versions mentioned in the advisory, as these releases contain the necessary sanitization fixes. Additionally, implementing comprehensive content security policies, regular security code reviews, and automated vulnerability scanning can help prevent similar issues from emerging in future deployments. The ATT&CK framework categorizes this as a web application attack vector under the technique of code injection, specifically targeting the execution of arbitrary commands through insecure input handling mechanisms.