Executive brief
GitProxy is a Git proxy service used to mediate and control access to Git repositories hosted on GitHub. An attacker with push access can inject malicious commits into the repository that never appear in visible branch history but remain accessible directly by commit URL, allowing them to secretly exfiltrate sensitive data like credentials or proprietary code without leaving any audit trail in the repository's normal view.
Technical details
The vulnerability is a pack validation bypass (CWE-200, exposure of sensitive data) in GitProxy's packfile handling. The proxy validates only the ref-update line but does not inspect the actual contents of the Git packfile being pushed. An attacker can craft a packfile containing extra commits beyond those expected from the ref update, and since the code only runs `git rev-list oldOid..newOid` without verifying which commits actually arrived, these "hidden" commits are stored by GitHub but never referenced by any branch. The attack requires authentication (an account with push rights to a repository) and network access to the proxy. Although the hidden commits do not appear in UI or branch graphs, GitHub serves them via direct commit URLs indefinitely, enabling data exfiltration. The vulnerability is patched in version 1.19.2 and later.
Affected products
- FINOS GitProxy before 1.19.2
Timeline
- 2025-07-30: disclosed
- 2025-07-30: patched: Version 1.19.2 and 2.0.0