CVE-2026-6966 Details
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.
A vulnerability in the awslabs Tough library and its command-line utility, Tuftool, prior to versions 0.22.0 and 0.15.0 respectively, allows remote authenticated users to bypass the TUF signature threshold requirement. This is achieved by duplicating a valid cryptographic signature, which can then be used to forge delegated role metadata. The issue arises from improper verification of signature uniqueness in delegated role validation.
Users are advised to upgrade to Tough version 0.22.0 or later and Tuftool version 0.15.0 or later. Instructions for upgrading are available in the Tough and Tuftool GitHub repositories.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 24, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://aws.amazon.com/security/security-bulletins/2026-019-aws/ | AMZN | Vendor Advisory |
| https://crates.io/crates/tough/0.22.0 | AMZN | Product |
| https://crates.io/crates/tuftool/0.15.0 | AMZN | Product |
| https://github.com/awslabs/tough/releases/tag/tough-v0.22.0 | AMZN | Release Notes |
| https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0 | AMZN | Release Notes |
| https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x | AMZN | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-347 | Improper Verification of Cryptographic Signature | AMZN |
Affected Products
| Product | Versions |
|---|---|
| amazon tough | < 0.22.0 |
CPE
Remediation
| |
| amazon tuftool | < 0.15.0 |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | AMZN |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 6, 2026 | Initial Analysis | [email protected] |
| Apr 24, 2026 | CVE Modified | AMZN |
| Apr 24, 2026 | New CVE Received | AMZN |