CVE-2023-45878: 
NixOS vulnerability analysis and mitigation

GibbonEdu Gibbon version 25.0.1 and before contains an Arbitrary File Write vulnerability in the rubrics_visualise_saveAjax.phps component. The vulnerability exists because the endpoint does not require authentication and accepts parameters that allow writing arbitrary files to the system (USD Advisory, NVD).

The vulnerability exists in the rubrics_visualise_saveAjax.php file which accepts img, path and gibbonPersonID as POST parameters without authentication. The img parameter is expected to be a base64 encoded image that gets decoded and written to a file path specified by the path parameter, concatenated with the installation's absolute path. This allows attackers to write arbitrary PHP files by crafting malicious base64 encoded content (USD Advisory). The vulnerability has been assigned a CVSS v3.1 base score of 9.8 CRITICAL (NVD).

This vulnerability allows unauthenticated attackers to upload arbitrary files to the application and achieve remote code execution on the underlying system by crafting fake images that can be stored as PHP files (USD Advisory).

The vulnerability is exploitable remotely without requiring authentication. A proof-of-concept exploit has been published demonstrating how an attacker can write a malicious PHP file to achieve code execution (USD Advisory).

The vulnerability has been fixed in commit '226d83568cf3d447c4d86d4e5aba2c6e6289045d'. Users should upgrade to a version after this commit. The recommended fix is to ensure that only valid file types can be uploaded (USD Advisory).