CVE-2023-5512: 
GitLab vulnerability analysis and mitigation

An issue has been discovered in GitLab CE/EE affecting all versions from 16.3 before 16.4.4, all versions starting from 16.5 before 16.5.4, all versions starting from 16.6 before 16.6.2. The vulnerability allows file integrity to be compromised when specific HTML encoding is used for file names, leading to incorrect representation in the UI (GitLab Release, NVD).

The vulnerability stems from improper handling of character encoding in file names, specifically when the %2f character is used. GitLab's web interface does not perform proper additional encoding, which can lead to incorrect representation of file names and content. The issue has been assigned a CVSS v3.1 base score of 4.8 (Medium) with the vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N. The vulnerability is classified as CWE-94 (Improper Control of Generation of Code) (NVD).

This vulnerability enables attackers to create repositories with malicious content that appears harmless in GitLab's web interface. When users download or clone the repository, they may unknowingly obtain files with malicious content, potentially resulting in the execution of arbitrary commands on the victim's system. For example, a file named dir%2f__hello__.sh could display different contents in the web interface compared to its actual contents when downloaded (GitLab Issue).

The vulnerability has been fixed in GitLab versions 16.4.4, 16.5.4, and 16.6.2. Users are strongly recommended to upgrade to these patched versions immediately. GitLab.com has already been updated with the patched version (GitLab Release).