{"id":"CVE-2026-6966","title":"Signature Threshold Bypass in awslabs/tough Delegated Roles","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 sig…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N","cvssSource":"cna","cwe":["CWE-347"],"vendor":"AWS","product":"tough","affected":["tough >= 0.9.0 <= 0.21","tuftool <= 0.14"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-04-24T20:15:12.033311Z"},"published":"2026-04-24","updated":"2026-10-20","sourceUpdated":"2026-10-20T18:24:24.155Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-6966","references":[{"url":"https://aws.amazon.com/security/security-bulletins/2026-019-aws/"},{"url":"https://github.com/awslabs/tough/releases/tag/tough-v0.22.0"},{"url":"https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0"},{"url":"https://crates.io/crates/tough/0.22.0"},{"url":"https://crates.io/crates/tuftool/0.15.0"},{"url":"https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x"}],"tags":["cve.org"],"epss":0.0037,"epssPercentile":0.29461,"ingestedAt":"2026-10-20T19:16:14.551Z","slug":"CVE-2026-6966","body":"## Overview\n\nImproper 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.\n\n\n\nWe recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.\n\n## Affected\n\n- `tough >= 0.9.0 <= 0.21`\n- `tuftool <= 0.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}