# CVE-2026-6966: Signature Threshold Bypass in awslabs/tough Delegated Roles

> CVE-2026-6966: Signature Threshold Bypass in awslabs/tough Delegated Roles. CVSS 5.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-6966
Last updated: 2026-10-20T19:17:51Z

- Published: 2026-04-24 19:38 UTC · Updated: 2026-10-20 19:17 UTC · Assigner: AMZN
- CVSS: 5.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
- EPSS: 0.28%, 21th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-347

## Description

Improper verification of cryptographic signature uniqueness in delegated role validation in awslabs/tough before tough-v0.22.0 allows remote authenticated users to bypass the TUF signature threshold requirement by duplicating a valid signature, causing the client to accept forged delegated role metadata. We recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.

## Affected vendors and products

- AWS: tough
- AWS: tuftool

## Tracked companies

- [Amazon Web Services](https://rewindex.com/company/aws.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-6966)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-6966)
- [https://aws.amazon.com/security/security-bulletins/2026-019-aws/](https://aws.amazon.com/security/security-bulletins/2026-019-aws/)
- [https://crates.io/crates/tough/0.22.0](https://crates.io/crates/tough/0.22.0)
- [https://crates.io/crates/tuftool/0.15.0](https://crates.io/crates/tuftool/0.15.0)
- [https://github.com/awslabs/tough/releases/tag/tough-v0.22.0](https://github.com/awslabs/tough/releases/tag/tough-v0.22.0)
- [https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0](https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0)
- [https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x](https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-6966 · Markdown: https://rewindex.com/cve/CVE-2026-6966.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-6966 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:09:23.637Z