A path traversal vulnerability was identified in GitHub Enterprise Server that allowed remote code execution when building a GitHub Pages site. To exploit this vulnerability, an attacker would need permission to create and build a GitHub Pages site on the instance. This vulnerability was fixed in versions 3.3.17, 3.4.12, 3.5.9, 3.6.5 and 3.7.2. This vulnerability was reported via the GitHub Bug Bounty program.
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.