sourcegraph is a code intelligence platform. As a site admin it was possible to execute arbitrary commands on Gitserver when the experimental `customGitFetch` feature was enabled. This experimental feature has now been disabled by default. This issue has been patched in version 4.1.0.
https://github.com/sourcegraph/sourcegraph/security/advisories/GHSA-4qhq-4x4h-fxm8