awslabs/tough is Missing Delegated Metadata Validation

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-6967: 0.25% estimated exploitation activity in the next 30 days; percentile 16.83 (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 Missing expiration, hash, and length enforcement in delegated metadata validation in awslabs/tough before tough-v0.22.0 allows remote authenticated users with delegated signing authority to bypass TUF specification integrity checks for delegated targets metadata and poison the local metadata cache, because loaddelegations does not apply the same validation checks as the top-level targets metadata path. Impact The tough library, prior to 0.22.0, does not properly verify delegated target metadata. It allows someone with write access to the metadata to serve expired or otherwise invalid targets from a TUF repository which tough will then trust rather than reject. Impacted Versions: tough 0.9.0 through 0.21.x, tuftool through 0.14.x Patches This issue has been addressed in tough version 0.22.0 and tuftool version 0.15.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. Workarounds No workarounds to…

Published by the source

5 May 2026, 18:46 UTC

Last modified by the source

5 May 2026, 18:46 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4v58-8p28-2rq3

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# Patch Next advisory brief: CVE-2026-6967

Advisory: awslabs/tough is Missing Delegated Metadata Validation
IDs: CVE-2026-6967, GHSA-4v58-8p28-2rq3
Record: https://patchnext.com/advisories/cve-2026-6967 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: tough 0.22.0; tuftool 0.15.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io tough: affected >= 0.9.0, < 0.22.0; fixed in 0.22.0
- crates.io tuftool: affected < 0.15.0; fixed in 0.15.0

## Suggested inspection (read-only)
- crates.io tough: check the installed version with your package manager.
- crates.io tuftool: 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 tough, tuftool.
- 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-4v58-8p28-2rq3 (GitHub-reviewed advisory GHSA-4v58-8p28-2rq3 lists affected ranges: crates.io tough >=0.9.0 =0 <0.15.0)

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