Gitea: Cross-repository issue/comment attachment re-linking can expose private attachment content

Exploitation

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

CVSS

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

EPSS

• CVE-2026-57886: 0.31% estimated exploitation activity in the next 30 days; percentile 24.18 (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 Gitea's issue and comment attachment update paths accept attachment UUIDs without verifying that each attachment belongs to the target issue/comment repository. If an authenticated attacker knows a victim attachment UUID, they can re-link that attachment to an attacker-controlled issue or comment, causing later attachment access checks to use the attacker's repository authorization context. Affected - Component: web issue/comment attachment handling. - Confirmed version: main commit a39b2775edcb3ba53def96794491b91335117d81 (v1.27.0-dev-352-ga39b2775ed). - Fixed in: not fixed at the time of validation. - Other versions: not exhaustively tested. The affected code path appears structurally similar to versions that contain the current issue/comment attachment update logic. Description / Root Cause files[] values from issue/comment edit flows are passed to updateAttachments in routers/web/repo/issue.go:589-629. That helper calls: - models/issues/issueupdate.go:267-278…

Published by the source

21 Jul 2026, 20:22 UTC

Last modified by the source

21 Jul 2026, 20:22 UTC

Source last checked

26 Oct 2026, 15:27 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6c6r-5xr4-cr5m

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# Patch Next advisory brief: CVE-2026-57886

Advisory: Gitea: Cross-repository issue/comment attachment re-linking can expose private attachment content
IDs: CVE-2026-57886, GHSA-6c6r-5xr4-cr5m
Record: https://patchnext.com/advisories/cve-2026-57886 (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: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code.gitea.io/gitea 1.27.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.gitea.io/gitea: affected < 1.27.0; fixed in 1.27.0

## Suggested inspection (read-only)
- Go code.gitea.io/gitea: 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 code.gitea.io/gitea.
- 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-6c6r-5xr4-cr5m (GitHub-reviewed advisory GHSA-6c6r-5xr4-cr5m lists affected ranges: Go code.gitea.io/gitea >=0 <1.27.0)

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