CVE-2026-17556 Path traversal in Enterprise Server
Unauthenticated attackers can delete arbitrary files and directories on GitHub Enterprise Server instances via path traversal in the X-GitHub-Request-Id header.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-17556?
CVE-2026-17556 is a high-severity path traversal vulnerability in Github Enterprise Server, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-22
Which versions are affected by CVE-2026-17556?
It affects 1 product.
Products include Github Enterprise Server.
How do I fix CVE-2026-17556?
No fix has been published for CVE-2026-17556 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-17556 being exploited?
There is no known exploitation of CVE-2026-17556 in the wild and no public exploit code.
Other vulnerabilities in Github Enterprise Server
- CVE-2024-4985 Auth bypass in Enterprise Server
- CVE-2022-23739 Missing authorization in GitHub Enterprise Server
- CVE-2022-46255 Improper Limitation of a Pathname to a Restricted Directory in GitHub Enterprise Server leading to RCE
- CVE-2021-22869 Improper access control in GitHub Enterprise Server allows self-hosted runners to execute outside their control group
- CVE-2024-9487 Auth bypass in Enterprise Server
Sources
Also known as GHSA-h3g3-4265-wv56.