Gitea Actions Artifacts V4 signed URL HMAC ambiguity allows cross-repository artifact read and cross-task upload-state write

Exploitation

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

CVSS

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

EPSS

• CVE-2026-58426: 0.23% estimated exploitation activity in the next 30 days; percentile 14.32 (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 Actions Artifacts V4 signed upload/download URLs can be rewritten to access a different running task and repository context while preserving the original HMAC signature. An attacker with permission to run a Gitea Actions job can turn a signed URL for an attacker-controlled artifact into a URL that reads artifacts from another task context, or writes attacker-controlled data into another task's artifact upload staging context, including in a private repository. This is one vulnerability with two exploit paths: - DownloadArtifact: cross-task/cross-repository artifact read, giving C:H. - UploadArtifact: cross-task artifact staging write and metadata mutation, giving I:H. Details The root cause is that the V4 artifact signed URL signature is built from raw concatenated fields without delimiters or length-prefixing: Affected code: routers/api/actions/artifactsv4.go:164-171. Because artifactName, taskID, and artifactID are concatenated without boundaries, two different URL…

Published by the source

27 Jul 2026, 15:32 UTC

Last modified by the source

27 Jul 2026, 17:00 UTC

Source last checked

26 Oct 2026, 15:27 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hg5r-vq93-9fv6

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GO-2026-6060

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# Patch Next advisory brief: CVE-2026-58426

Advisory: Gitea Actions Artifacts V4 signed URL HMAC ambiguity allows cross-repository artifact read and cross-task upload-state write
IDs: CVE-2026-58426, GHSA-hg5r-vq93-9fv6
Record: https://patchnext.com/advisories/cve-2026-58426 (revision 2, 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 9.6)
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 1.26.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.gitea.io/gitea: affected >= 1.22.0, < 1.26.2; fixed in 1.26.2

## 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://osv.dev/vulnerability/GO-2026-6060 (OSV record GO-2026-6060 lists affected ranges: Go code.gitea.io/gitea >=1.22.0 <1.26.2 (fixed))
- Verified: https://github.com/advisories/GHSA-hg5r-vq93-9fv6 (GitHub-reviewed advisory GHSA-hg5r-vq93-9fv6 lists affected ranges: Go code.gitea.io/gitea >=1.22.0 <1.26.2)

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