CVE-2026-6335: XSS in GitLab 18.11

Successful exploitation of CVE-2026-6335 could allow an attacker to impersonate another user within GitLab, potentially gaining access to sensitive data or performing actions on their behalf. This could include viewing private repositories, modifying project settings, or even accessing administrative functions if the targeted user possesses elevated privileges. The impact is amplified if the targeted user has access to critical infrastructure or sensitive data, leading to a broader compromise of the GitLab instance. The ability to execute code within another user's browser session represents a significant security risk, as it bypasses traditional authentication mechanisms.

1. 予約済み2026-04-15
2. 公開日2026-05-14

The primary mitigation for CVE-2026-6335 is to immediately upgrade GitLab to version 18.11.3 or later. If upgrading is not immediately feasible, consider implementing stricter input validation on user-supplied data within GitLab. While not a direct fix, this can help reduce the attack surface. Review GitLab's security configuration and ensure that all security features are enabled and properly configured. Monitor GitLab logs for any suspicious activity that might indicate exploitation attempts.