CVE-2026-6966 json
Signature Threshold Bypass in awslabs/tough Delegated Roles
published 2026-04-24 6 mo ago modified 2026-10-26 13 d ago also GHSA-8m7c-8m39-rv4x , EUVD-2026-25627
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 20%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- crates.io tough 0.22.0
- crates.io tuftool 0.15.0
- amazon tough 0.22.0
- amazon tuftool 0.15.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N |
| CNA | 4.0 | 7.0 | 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 |
| CNA | 4.0 | 7.0 | 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:X/V:X/RE:X/U:X |
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | tough | <0.22.0 |
0.22.0 |
| crates.io | tuftool | <0.15.0 |
0.15.0 |
Affected products
- AWS tough
- AWS tuftool
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/awslabs/tough/releases/tag/tough-v0.22.0
patch, web, release-notes
-
github.com
/awslabs/tough/releases/tag/tuftool-v0.15.0
patch, web, release-notes
-
crates.io
/crates/tough/0.22.0
patch, web, product
-
crates.io
/crates/tuftool/0.15.0
patch, web, product
-
aws.amazon.com
/security/security-bulletins/2026-019-aws/
vendor-advisory
-
github.com
/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x
third-party-advisory, web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-6966
advisory
-
aws.amazon.com
/security/security-bulletins/2026-019-aws
web
-
github.com
/awslabs/tough
package
Sources
- CVE List CVE-2026-6966
- GitHub Advisory GHSA-8m7c-8m39-rv4x
- NVD CVE-2026-6966
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