CVE-2018-9244 in Community Edition
Summary
by MITRE
GitLab Community and Enterprise Editions version 9.2 up to 10.4 are vulnerable to XSS because a lack of input validation in the milestones component leads to cross site scripting (specifically, data-milestone-id in the milestone dropdown feature). This is fixed in 10.6.3, 10.5.7, and 10.4.7.
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Analysis
by VulDB Data Team • 02/27/2023
The vulnerability identified as CVE-2018-9244 affects GitLab Community and Enterprise Edition installations across versions 9.2 through 10.4, representing a significant cross-site scripting weakness that could enable attackers to execute malicious scripts within the context of a victim's browser session. This flaw specifically manifests within the milestones component of GitLab's web interface, where insufficient input validation permits malicious data to be injected into the milestone dropdown feature. The vulnerability is particularly concerning as it affects a core project management functionality that is widely used across development teams and organizations relying on GitLab for their source code management and collaboration needs.
The technical implementation of this XSS vulnerability stems from inadequate sanitization of the data-milestone-id parameter within the milestone dropdown feature. When users interact with the milestones component, the application fails to properly validate or escape user-supplied input before rendering it in the web interface. This allows an attacker to craft malicious payloads that can be executed when other users view the affected milestone dropdown, potentially leading to session hijacking, credential theft, or unauthorized actions within the GitLab environment. The vulnerability operates under CWE-79 which categorizes improper neutralization of input during web page generation as a fundamental weakness in web application security. This weakness is classified as a client-side vulnerability that leverages the trust relationship between the web application and the user's browser.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to manipulate project data, access sensitive information, or perform unauthorized actions within the GitLab instance. Since GitLab serves as a central hub for development workflows, the compromise of a single milestone component could potentially provide attackers with access to confidential project information, code repositories, or collaboration data. The vulnerability affects both community and enterprise editions, meaning that organizations of all sizes using these GitLab versions are at risk, particularly those with multiple users interacting with project milestones. The attack vector requires minimal privileges as the vulnerability exists in the user interface rendering logic rather than requiring administrative access or elevated permissions. According to ATT&CK framework, this vulnerability maps to T1059.007 which covers scripting languages, and T1566.001 which covers spearphishing attachments, as attackers could potentially use this vulnerability to deliver malicious payloads through compromised milestone data.
Organizations affected by this vulnerability should immediately implement mitigations including updating to the patched versions 10.6.3, 10.5.7, or 10.4.7 as specified in the advisory. The patch addresses the root cause by implementing proper input validation and sanitization for the data-milestone-id parameter within the milestone dropdown component. Additional defensive measures include implementing content security policies to limit script execution, monitoring user activity for suspicious milestone modifications, and conducting security awareness training for developers who may inadvertently introduce malicious data into project components. Organizations should also review their existing milestone data for potential malicious payloads and consider implementing web application firewalls to detect and block suspicious input patterns. The vulnerability highlights the importance of input validation across all user-facing components of web applications and demonstrates how seemingly minor functionality can present significant security risks when proper sanitization is not implemented.