GitLab CE/EE <=19.1.7/19.2.5/19.3.1 - Arbitrary File Read
Description
GitLab CE/EE contains an unauthenticated arbitrary file read. Workhorse, the reverse proxy in front of Rails, matches upload routes using EscapedPath() and path.Clean without decoding percent sequences, while Puma decodes them before routing to Grape. Appending a trailing slash to commits or percent-encoding a static path segment as %63ommits therefore bypasses Workhorse upload route rewriting, and Rails reaches file_params_from_body_upload() which opens the path given in the file.path parameter before authenticate! is enforced. On the application/x-www-form-urlencoded branch the file bytes are handed to Rack::Utils.parse_nested_query, and any invalid percent sequence raises an ArgumentError whose message is interpolated into the HTTP 400 response body, disclosing file content to an unauthenticated caller.
Severity
CVSS Score
10
Exploit Probability
92%
Affected Product
gitlab