CVE-2026-17556
published 2026-08-05CVE-2026-17556: A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to delete arbitrary files and directories on…
PriorityP263critical9.1CVSS 3.1
AVNACLPRNUINSUCNIHAH
EPSS
0.50%
42.0th percentile
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.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github | enterprise_server | < 3.17.19 | 3.17.19 |
| github | enterprise_server | 3.17.0 – 3.17.18 | — |
| github | enterprise_server | >= 3.18.0 < 3.18.13 | 3.18.13 |
| github | enterprise_server | 3.18.0 – 3.18.12 | — |
| github | enterprise_server | >= 3.19.0 < 3.19.10 | 3.19.10 |
| github | enterprise_server | 3.19.0 – 3.19.9 | — |
| github | enterprise_server | >= 3.20.0 < 3.20.6 | 3.20.6 |
| github | enterprise_server | 3.20.0 – 3.20.5 | — |
| github | enterprise_server | >= 3.21.0 < 3.21.4 | 3.21.4 |
| github | enterprise_server | 3.21.0 – 3.21.3 | — |
CVSS provenance
nvdv3.19.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
nvdv4.08.8HIGHCVSS: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:X/V:X/RE:X/U:X
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VulDB
GitHub Enterprise Server up to 3.21.3 X-GitHub-Request-Id path traversal
vuldb·2026-08-05·CVSS 8.8
CVE-2026-17556 [HIGH] GitHub Enterprise Server up to 3.21.3 X-GitHub-Request-Id path traversal
A vulnerability classified as critical was found in GitHub Enterprise Server up to 3.17.18/3.18.12/3.19.9/3.20.5/3.21.3. This vulnerability affects unknown code. The manipulation of the argument X-GitHub-Request-Id results in path traversal.
This vulnerability is known as CVE-2026-17556. It is possible to launch the attack remotely. No exploit is available.
Upgrading the affected component is advised.
GHSA
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
ghsa_unreviewed·2026-08-05
CVE-2026-17556 [HIGH] CWE-22 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
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
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://docs.github.com/en/[email protected]/admin/release-notes#3.17.19https://docs.github.com/en/[email protected]/admin/release-notes#3.18.13https://docs.github.com/en/[email protected]/admin/release-notes#3.19.10https://docs.github.com/en/[email protected]/admin/release-notes#3.20.6https://docs.github.com/en/[email protected]/admin/release-notes#3.21.4
2026-08-05
Published