CVE-2026-6966
Signature Threshold Bypass in awslabs/tough Delegated Roles
- State
- Published
- Severity
- 7.0 High
- Published
- Apr 24, 2026
- Updated
- Oct 20, 2026
- Reserved
- Apr 24, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.0 High | 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 | AMZN |
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N | AMZN |
Weaknesses
- CWE-347 Improper Verification of Cryptographic Signature
Affected Products
| Product | Versions |
|---|---|
toughAWS |
|
tuftoolAWS |
|
References
- https://aws.amazon.com/security/security-bulletins/2026-019-aws/vendor-advisory
- https://github.com/awslabs/tough/releases/tag/tough-v0.22.0patch
- https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0patch
- https://crates.io/crates/tough/0.22.0patch
- https://crates.io/crates/tuftool/0.15.0patch
- https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4xthird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.