Vulnerability details

Gogs is an open source self-hosted Git service. Prior to 0.14.3, (*Repository).UploadRepoFiles checks for symlinks only on the leaf of the upload target (osx.IsSymlink(targetPath)). The siblings UpdateRepoFile, DeleteRepoFile, and GetDiffPreview use hasSymlinkInPath, which lstats every component — UploadRepoFiles is the lone outlier. An attacker with repo-write access plus a multipart upload whose filename contains a literal backslash (preserved by filepath.Base on Linux, then converted to / by pathx.Clean) redirects the write through a previously-committed directory symlink. iox.CopyFile opens the destination with os.Create (no O_NOFOLLOW), so the kernel follows the parent symlink and writes attacker bytes anywhere the gogs UID can write — ~git/.ssh/authorized_keys → SSH foothold, or <repo>.git/hooks/post-receive → next-push RCE. This vulnerability is fixed in 0.14.3.

• https://github.com/gogs/gogs/pull/8332 x_refsource_MISC
• https://github.com/gogs/gogs/commit/04cb8afbb01d855454e59977a1cdbf522ea1db31 x_refsource_MISC
• https://github.com/gogs/gogs/releases/tag/v0.14.3 x_refsource_MISC
• https://github.com/gogs/gogs/security/advisories/GHSA-89mr-xqfv-758m x_refsource_CONFIRM