CVE-2026-17556
Description
A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. The X-GitHub-Request-Id request header was used without sanitization as a filesystem path segment for the upload buffer directory, so a traversal value pointed the buffer at an arbitrary path and the deferred cleanup routine recursively removed the traversed target. Exploitation required only network reachability to the instance and no authentication, and it worked even when private mode was enabled. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.4, 3.20.6, 3.19.10, 3.18.13 and 3.17.19. This vulnerability was reported via the GitHub Bug Bounty program.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.19
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.13
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.10
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.6
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.4
CWEs
CWE-22
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.