CVE-2026-6966

Signature Threshold Bypass in awslabs/tough Delegated Roles

Published Apr 24, 2026 CVSS 4.0 · 7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-8m7c-8m39-rv4x awslabs/tough Delegated Roles have a Signature Threshold Bypass
History
Type Values Removed Values Added
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. 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.
CPEs cpe:2.3:a:aws:tough:*:*:*:*:*:*:*:*
cpe:2.3:a:aws:tuftool:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Amazon
Amazon tough
Amazon tuftool
CPEs cpe:2.3:a:amazon:tough:*:*:*:*:*:rust:*:*
cpe:2.3:a:amazon:tuftool:*:*:*:*:*:rust:*:*
Vendors & Products Amazon
Amazon tough
Amazon tuftool
Type Values Removed Values Added
First Time appeared Aws
Aws tough
Aws tuftool
Vendors & Products Aws
Aws tough
Aws tuftool
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Signature Threshold Bypass in awslabs/tough Delegated Roles
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N'}

cvssV4_0

{'score': 7, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
AMZN
Published
Updated
Oct 20, 2026, 6:24 PM
Reserved
Apr 24, 2026, 4:15 PM
Status
Modified
Published
Apr 24, 2026, 8:16 PM
Modified
Oct 26, 2026, 9:10 PM