Gogs: Cross-repository LFS object overwrite via missing content hash verification

Exploitation

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

CVSS

9.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L

EPSS

• CVE-2026-25921: 0.37% estimated exploitation activity in the next 30 days; percentile 31.22 (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 Overwritable LFS object across different repos leads to supply-chain attack, all LFS objects are vulnerable to be maliciously overwritten by malicious attackers. Details Gogs store all LFS objects in the same place, no isolation between different repositories. (repo id not concatenated to storage path) https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/lfsutil/storage.go#L52-L58 Gogs does not verify uploaded LFS file content against its claimed SHA-256, meaning attackers can manipulate the uploaded file like injecting backdoor. https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/lfsutil/storage.go#L79-L89 Here's the comment that trust client to retry upload allowing them to overwrite. However, this assumption does not hold in the case of a malicious client. https://github.com/gogs/gogs/blob/7a2dffa95ac64f31c8322cb50d32694b05610144/internal/route/lfs/basic.go#L111-L113 PoC 1. User (admin1) upload a LFS object…

Published by the source

5 Mar 2026, 19:14 UTC

Last modified by the source

5 Mar 2026, 22:28 UTC

Source last checked

26 Oct 2026, 15:15 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cj4v-437j-jq4c

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

# Patch Next advisory brief: CVE-2026-25921

Advisory: Gogs: Cross-repository LFS object overwrite via missing content hash verification
IDs: CVE-2026-25921, GHSA-cj4v-437j-jq4c
Record: https://patchnext.com/advisories/cve-2026-25921 (revision 1, source checked 26 Oct 2026, 15:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
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 0.14.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go gogs.io/gogs: affected <= 0.14.1; fixed in 0.14.2

## 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-cj4v-437j-jq4c (GitHub-reviewed advisory GHSA-cj4v-437j-jq4c lists affected ranges: Go gogs.io/gogs >=0 <=0.14.1)

Commands are suggestions: review each one before running it.