A security vulnerability (CVE-2023-3993) has been discovered in GitLab's Enterprise Edition (EE) that could expose access tokens in server logs. This issue affects all versions starting from 14.3 before 16..8, all versions starting from 16.1 before 16.1.3, and all versions starting from 16.2 before 16.2.2. Specifically, the vulnerability is tied to a particular endpoint on the affected GitLab EE installations.

In this post, we will dive into the details of this vulnerability, including code snippets, original references, and recommended actions to mitigate the risk of exploitation.

Vulnerability Details

The vulnerability lies in the way GitLab EE processes and logs queries made to a specific endpoint within the application. When a user queries this endpoint, their access token may be inadvertently exposed in server logs, posing a significant security risk.

Here's a code snippet that explains the flawed behavior

def process_query(query, access_token):
    # logs the query and access token in server logs
    log_query(query, access_token) 
    # ...
    # rest of the logic

def log_query(query, access_token):
    log_message = f'[{time.now()}] {query} {access_token}'

By including the access_token in the log_query() function, sensitive user information is being leaked into the server logs. Malicious actors with access to these logs can extract access tokens and potentially gain unauthorized access to user accounts and data.

Exploit Details

At the moment, there are no known public exploits for this vulnerability. Nonetheless, it is still essential to treat this issue with urgency, given the potential impact if left unchecked. Access tokens provide crucial access to user accounts, and a malicious actor could assume a user's identity to carry out privilege escalation, data theft, or worse.

Mitigation Steps

To protect against this vulnerability, GitLab has released patches for the affected versions. Administrators should take the following steps:

Upgrade to GitLab EE version 16..8, 16.1.3, or 16.2.2, depending on your current version.

2. Review server logs for any instances of leaked access tokens. If identified, immediately revoke and regenerate affected tokens, and notify affected users.

3. Regularly update GitLab EE to ensure that your installation is running the latest security patches and updates.

Staying diligent and adhering to a strict patch management process can drastically improve your organization's security posture. Moreover, regularly reviewing and auditing server logs can help identify abnormalities or instances of unauthorized access.


CVE-2023-3993 is a critical security issue in GitLab EE that could have significant implications for affected organizations. By applying patches and following the recommended mitigation steps, you can protect your organization from potential exploitation. Be proactive, stay informed, and prioritize the security of your infrastructure.


Published on: 08/02/2023 01:15:00 UTC
Last modified on: 08/04/2023 19:23:00 UTC