CVE-2025-1257 - Denial of Service Vulnerability in GitLab EE Affecting API Inputs

A severe Denial of Service (DoS) vulnerability, identified as CVE-2025-1257, has been discovered in GitLab EE (Enterprise Edition). This vulnerability is present in all version of GitLab EE, starting from 12.3 before 17.7.7, 17.8 prior to 17.8.5, and 17.9 prior to 17.9.2. An attacker can potentially exploit this vulnerability by manipulating specific API inputs, causing a DoS condition and disrupting the normal functionality of the affected GitLab instances. In this post, we will provide a detailed overview of the CVE-2025-1257 vulnerability, including its origin, impact, and methods to mitigate the risk it poses.

Code Snippet

Given below is a simple code snippet that demonstrates an example of the vulnerability present in the affected GitLab instances:

import requests

TARGET_URL = "https://target-gitlab-instance.com/api/v4";
API_KEY = "your-api-key"

headers = {
    "Private-Token": API_KEY,
}

data = {
    "malicious_key": "malicious_value"  # Manipulated API input
}

response = requests.post(TARGET_URL + "/projects", headers=headers, data=data)

print(response.status_code)

In the code snippet above, the attacker manipulates an API input ("malicious_key": "malicious_value") and sends a POST request to the GitLab instance, causing unexpected behavior on the affected system. This particular input can lead to a Denial of Service condition, which disrupts the normal operation of the targeted GitLab instances.

Original References

The vulnerability report and detailed information regarding CVE-2025-1257 can be found in the following references:

1. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-1257
2. https://gitlab.com/gitlab-org/gitlab/-/issues/1257
3. https://gitlab.com/gitlab-org/gitlab/-/merge_requests/7765

Exploit Details

An attacker exploiting the CVE-2025-1257 vulnerability can cause a denial of service condition on the targeted GitLab instance, rendering it unresponsive and unavailable for a certain period. The attacker would typically use manipulated API inputs, similar to the code snippet provided above, in a POST request, causing the affected GitLab instance to consume excessive resources and eventually become unavailable.

Mitigation

To mitigate the CVE-2025-1257 vulnerability and protect GitLab instances from potential exploitation, the GitLab team has released patches and updates for the affected versions. The fixed versions are:

17.9.2

It is strongly advised that GitLab administrators update their instances to the latest patched versions mentioned above, and refer to the following GitLab security advisory for additional guidance on securing your GitLab deployments:

https://about.gitlab.com/releases/2025/08/25/gitlab-17-7-7-17-8-5-and-17-9-2-security-release

Conclusion

CVE-2025-1257 is a significant Denial of Service vulnerability affecting multiple GitLab EE versions that could be exploited by manipulating specific API inputs. The potential impact on affected systems ranges from temporary unavailability to sustained disruption of service. Administrators are encouraged to implement the recommended patches and updates to mitigate the risk and protect their GitLab instances from potential exploitation.

Timeline

Published on: 03/13/2025 06:15:36 UTC