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Vulnerability record · CVE-2026-6966 · published 24 April 2026

CVE-2026-6966: Amazon tough improper verification of cryptographic signature vulnerability

Amazon · Tough

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.

7.0 CVSS 4.0 High EPSS 0.37% · top 71.7% CWE-347 · Improper verification of cryptographic signature
7.0CVSS 4.0 base score
0.37%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

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.

CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://aws.amazon.com/security/security-bulletins/2026-019-aws/ Vendor Advisory
https://crates.io/crates/tough/0.22.0 Product
https://crates.io/crates/tuftool/0.15.0 Product
https://github.com/awslabs/tough/releases/tag/tough-v0.22.0 Release Notes
https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0 Release Notes
https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-6966), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.