Vulnerability record · CVE-2026-17556 · published 5 August 2026
CVE-2026-17556: Github enterprise server path traversal vulnerability
Github · Enterprise Server
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.
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/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://docs.github.com/en/[email protected]/admin/release-notes#3.17.19 | ProductRelease Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.18.13 | ProductRelease Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.19.10 | ProductRelease Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.20.6 | ProductRelease Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.21.4 | ProductRelease Notes |
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-17556), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
