Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.0 · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H · score source

EPSS

• CVE-2026-52811: 0.47% estimated exploitation activity in the next 30 days; percentile 41.03 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary (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 ONOFOLLOW), so the kernel follows the parent symlink and writes attacker bytes anywhere the gogs UID can write — ~git/.ssh/authorizedkeys → SSH foothold, or <repo.git/hooks/post-receive → next-push RCE. Windows builds are unaffected: filepath.Base treats \ as a separator (strips the multi-segment trick) and git defaults core.symlinks=false at checkout (committed mode-120000 entries become text files, not real…

Published by the source

23 Jun 2026, 17:09 UTC

Last modified by the source

21 Jul 2026, 13:40 UTC

Source last checked

26 Oct 2026, 15:27 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-89mr-xqfv-758m

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-52811

Advisory: Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym
IDs: CVE-2026-52811, GHSA-89mr-xqfv-758m
Record: https://patchnext.com/advisories/cve-2026-52811 (revision 1, source checked 26 Oct 2026, 15:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: gogs.io/gogs 0.14.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go gogs.io/gogs: affected < 0.14.3; fixed in 0.14.3

## Suggested inspection (read-only)
- Go gogs.io/gogs: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on gogs.io/gogs.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-89mr-xqfv-758m (GitHub-reviewed advisory GHSA-89mr-xqfv-758m lists affected ranges: Go gogs.io/gogs >=0 <0.14.3)

Commands are suggestions: review each one before running it.