A critical security vulnerability, CVE-2022-3478, has been discovered in GitLab, the popular DevOps platform where software developers can collaborate on code, manage projects, and deploy applications. This vulnerability affects all GitLab versions from 12.8 to 15.4.5, all 15.5 versions before 15.5.5, and all 15.6 versions before 15.6.1. The vulnerability opens the door to a Denial of Service (DoS) attack, permitting bad actors to upload a crafted NuGet package, potentially taking down a GitLab instance or rendering it inoperable.

In this long read, we will explore the technical details of CVE-2022-3478, provide example code snippets to illustrate the exploit, and refer to the original references, advisories, and patches provided by GitLab and security researchers.

Exploit Details

The CVE-2022-3478 vulnerability in GitLab can be exploited via a crafted NuGet package. NuGet is a package manager for the Microsoft development platform, and GitLab offers support for NuGet package repositories. The vulnerability stems from insufficient validation of NuGet package uploads, which allows an attacker to submit a malicious NuGet package containing an incredibly large .nuspec file. When GitLab processes the package, the server could become overwhelmed or crash, leading to a Denial of Service. The attacker does not need any special privileges or authentication to perform this attack, which makes the vulnerability even more critical.

Code Snippet

The following example demonstrates how an attacker could create a malicious NuGet package with an enormous .nuspec file:

<?xml version="1."?>
    <title>Example Malicious NuGet Package</title>
    <description>Evil payload to trigger DoS attack</description>
      <!-- Extremely large dependency list generated, possibly in the order of GBs -->

After creating the malicious package, the attacker can then upload it to a victim's GitLab instance using the NuGet command-line interface:

nuget push Malicious.Package.1...nupkg -ApiKey <API_KEY> -Source <GITLAB_INSTANCE_URL>

Original References & Recommendations

The vulnerability was first identified and reported by an independent security researcher on GitLab's official security issue tracker. The original report can be found here:

- GitLab Security Advisory: Denial of Service Attack using malicious NuGet package upload

In response to the vulnerability, GitLab has released patches for all affected versions

- GitLab 15.4.6: https://about.gitlab.com/releases/2022/11/25/security-release-gitlab-15-4-6-released/
- GitLab 15.5.5: https://about.gitlab.com/releases/2022/11/25/security-release-gitlab-15-5-5-released/
- GitLab 15.6.1: https://about.gitlab.com/releases/2022/11/25/gitlab-15-6-1-released/

As a user or administrator of a GitLab instance, it's of the utmost importance to update your GitLab installation to the latest version, which includes necessary security patches to mitigate the CVE-2022-3478 vulnerability. Keeping your software up-to-date, being cautious of package uploads, and monitoring your GitLab instance for suspicious activity are all essential security practices to follow.


CVE-2022-3478 is a critical security vulnerability that affects a large number of GitLab instances. By understanding the technical aspects of this vulnerability and applying the appropriate patches, you can protect your GitLab installation from potential DoS attacks. Don't delay in taking the necessary steps to secure your GitLab instance from this and other security threats.


Published on: 01/26/2023 21:15:00 UTC
Last modified on: 02/01/2023 17:16:00 UTC