Vulnerability in Amazon Tough
CVE-2026-6966
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Amazon Tough
- Amazon Tuftool
- AWS Tough — versions 0.22.0
- AWS Tuftool — versions 0.15.0
Weakness classification (CWE)
References
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory, Vendor Advisory)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Release Notes, patch)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Release Notes, patch)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Product, patch)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Product, patch)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (Vendor Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-6966?
- CVE-2026-6966 is a medium-severity vulnerability in Amazon Tough, classified under Improper Verification of Cryptographic Signature. CVSS score: 5.3/10. Published 2026-04-24.
- How severe is CVE-2026-6966?
- Medium severity. CVSS v3 base score is 5.3 out of 10.