# CVE-2026-6967: Missing Delegated Metadata Validation in awslabs/tough

> Authenticated users with delegated signing authority can bypass integrity checks and poison the local metadata cache in the tough library.

- **Severity:** High 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 20 Oct 2026
- **Also known as:** GHSA-4v58-8p28-2rq3

## What is CVE-2026-6967?

CVE-2026-6967 is a high-severity missing authorization vulnerability in AWS tough, published on 24 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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 load_delegations does not apply the same validation checks as the top-level targets metadata path.

We recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-6967?

4 open source packages ship an affected version, including tough and tuftool. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tough` | crates.io | From 0.9.0 | 0.22.0 |
| `tough` | crates.io | From 0.9.0 | 0.22.0 |
| `tuftool` | crates.io | All versions | 0.15.0 |
| `tuftool` | crates.io | All versions | 0.15.0 |

Products: Amazon Tough, Amazon Tuftool.

## How do I fix CVE-2026-6967?

Upgrade tough to 0.22.0 or later.

## Is CVE-2026-6967 being exploited?

There is no known exploitation of CVE-2026-6967 in the wild and no public exploit code.

## Other vulnerabilities in AWS tough

- [CVE-2020-15093](https://insights.sbomify.com/CVE-2020-15093/): Improper verification of signature threshold in tough (high 8.6)
- [CVE-2021-41149](https://insights.sbomify.com/CVE-2021-41149/): Improper sanitization of target names in tough (high 8.2)
- [CVE-2021-41150](https://insights.sbomify.com/CVE-2021-41150/): Improper sanitization of delegated role names in tough (high 8.2)
- [CVE-2026-6968](https://insights.sbomify.com/CVE-2026-6968/): Multiple Path Traversal Variants in awslabs/tough (high 7.1)
- [CVE-2026-6966](https://insights.sbomify.com/CVE-2026-6966/): Signature Threshold Bypass in awslabs/tough Delegated Roles (high 7.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6967 and fix it if it is affected.

What it is: CVE-2026-6967 is a high-severity missing authorization vulnerability in AWS tough, published on 24 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6967 in the wild and no public exploit code.

Affected packages and fixed versions:
- tough (crates.io): affected from 0.9.0; fixed in 0.22.0
- tough (crates.io): affected from 0.9.0; fixed in 0.22.0
- tuftool (crates.io): affected all versions; fixed in 0.15.0
- tuftool (crates.io): affected all versions; fixed in 0.15.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-6967/ (Markdown: https://insights.sbomify.com/CVE-2026-6967/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6967
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6967
- OSV: https://osv.dev/vulnerability/CVE-2026-6967

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6967/
Summaries are generated and may contain mistakes; the official description above is the record.