BuildKit is a toolkit used to convert source code into build artifacts. Before version 0.31.2, it was possible for a client with valid access permissions to the BuildKit control API to submit an upload request that causes files to be written outside the intended BuildKit-controlled state directory, due to improper limitation of pathname (CWE-22). This path traversal vulnerability could lead to unauthorized file writes outside the designated directory. The vulnerability is addressed in BuildKit version 0.31.2.

An attacker with valid permissions to access the BuildKit control API can exploit this vulnerability to write files outside the BuildKit-controlled directory, potentially leading to unauthorized file modification or system compromise within the scope of the BuildKit daemon's permissions. The vulnerability does not require bypassing authentication but does require valid access to the control API.

Upgrade BuildKit to version 0.31.2 or later, where this path traversal vulnerability has been fixed. Since the vulnerability requires valid permissions to the BuildKit control API, ensure that access to this API is properly restricted and monitored.