CVE-2026-17556Path traversal in GitHub Enterprise Server allowed unauthenticated deletion of instance storage via the X-GitHub-Request-Id header
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No exploitation reported and no EPSS estimate yet.
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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
- 8.8 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-22
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_P
- NVD analysis
- Analyzed
- Record last updated
- Aug 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
GitHub Enterprise Server github:enterprise_server (from the name) | from 3.17.0 through 3.17.18; fixed at 3.17.19; from 3.18.0 through 3.18.12; fixed at 3.18.13; from 3.19.0 through 3.19.9; fixed at 3.19.10; from 3.20.0 through 3.20.5; fixed at 3.20.6; from 3.21.0 through 3.21.3; fixed at 3.21.4 | CNA record |
github enterprise_server github:enterprise_server | before 3.17.19; from 3.18.0 before 3.18.13; from 3.19.0 before 3.19.10; from 3.20.0 before 3.20.6; from 3.21.0 before 3.21.4 | NVD |
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.19release-notes, product
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.13release-notes, product
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.10release-notes, product
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.6release-notes, product
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.4release-notes, product
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.