Signature Threshold Bypass in awslabs/tough Delegated Roles

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-6966
StatePUBLISHED
AssignerAMZN
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-24 20:16:28 UTC
Updated2026-04-24 21:16:19 UTC
DescriptionImproper 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.

Risk And Classification

Primary CVSS: v4.0 7 HIGH from ff89ba41-3aa1-4d27-914a-91399e9639e5

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:X/V:X/RE:X/U:X

Problem Types: CWE-347 | CWE-347 CWE-347: Improper Verification of Cryptographic Signature

VersionSourceTypeScoreSeverityVector
4.0ff89ba41-3aa1-4d27-914a-91399e9639e5Secondary7HIGHCVSS: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/C...
4.0CNACVSS7HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
3.1ff89ba41-3aa1-4d27-914a-91399e9639e5Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
3.1CNACVSS5.3MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
None
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
High
Sub Availability
None

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:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA AWS Tough unaffected 0.22.0 Not specified
CNA AWS Tuftool unaffected 0.15.0 Not specified

References

ReferenceSourceLinkTags
github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x ff89ba41-3aa1-4d27-914a-91399e9639e5 github.com
aws.amazon.com/security/security-bulletins/2026-019-aws ff89ba41-3aa1-4d27-914a-91399e9639e5 aws.amazon.com
github.com/awslabs/tough/releases/tag/tough-v0.22.0 ff89ba41-3aa1-4d27-914a-91399e9639e5 github.com
crates.io/crates/tough/0.22.0 ff89ba41-3aa1-4d27-914a-91399e9639e5 crates.io
crates.io/crates/tuftool/0.15.0 ff89ba41-3aa1-4d27-914a-91399e9639e5 crates.io
github.com/awslabs/tough/releases/tag/tuftool-v0.15.0 ff89ba41-3aa1-4d27-914a-91399e9639e5 github.com
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