CVE-2026-17556
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk38th percentile - higher than 38% of all known CVEs
Summary
GitHub Enterprise Server before version 3.22 has a path traversal vulnerability that allows 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. Exploitation of the X-GitHub-Request-Id header without sanitization as a filesystem path segment leads to data deletion.
Risk Assessment
The risk is complete loss of user data and repository integrity, which could lead to service disruption and severe consequences for the organization.
Recommendation
Immediately upgrade GitHub Enterprise Server to versions 3.21.4, 3.20.6, 3.19.10, 3.18.13, or 3.17.19, which contain the fix.
Original NVD description (English source)
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.