CVE-2026-17556
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.50%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.8 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.50% probability · 41th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- github/enterprise server
- Source
- product-cna@github.com
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.19Product, Release Notes
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.13Product, Release Notes
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.10Product, Release Notes
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.6Product, Release Notes
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.4Product, Release Notes
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.