{"id":"EUVD-2026-25627","revision":null,"records":[{"revision":"a21391f24fd241fb8223a0e5741e43be","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-6966","aliases":[],"title":"Signature Threshold Bypass in awslabs/tough Delegated Roles","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.\n\n\n\nWe recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.","state":0,"publishedAt":"2026-04-24T19:38:24.907+00:00","modifiedAt":"2026-10-20T18:24:24.155+00:00","affected":[{"ecosystem":"Vendor product","name":"tough","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"AWS\",\n                    \"product\": \"tough\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0.9.0\",\n                            \"lessThanOrEqual\": \"0.21\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"},{"ecosystem":"Vendor product","name":"tuftool","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"AWS\",\n                    \"product\": \"tuftool\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0\",\n                            \"lessThanOrEqual\": \"0.14\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N","score":5.3,"severity":"MEDIUM"},{"system":"CVSS 4.0","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","score":7,"severity":"HIGH"}],"references":["https://aws.amazon.com/security/security-bulletins/2026-019-aws/","https://github.com/awslabs/tough/releases/tag/tough-v0.22.0","https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0","https://crates.io/crates/tough/0.22.0","https://crates.io/crates/tuftool/0.15.0","https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-6966","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-6966","identifiers":["CVE-2026-6966"]},"retained":false,"historicalAffected":[]},{"revision":"f45222995e3e41bcbb83d642df84da98","observedAt":"2026-10-28T08:46:53.824+00:00","statement":{"source":"euvd","id":"EUVD-2026-25627","aliases":["CVE-2026-6966"],"title":"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 signat…","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.\n\n\n\nWe recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 4.0","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","score":7,"severity":null}],"references":["https://aws.amazon.com/security/security-bulletins/2026-019-aws/","https://github.com/awslabs/tough/releases/tag/tough-v0.22.0","https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0","https://crates.io/crates/tough/0.22.0","https://crates.io/crates/tuftool/0.15.0","https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-25627","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Apr 24, 2026, 7:38:24 PM","dateUpdated":"Oct 20, 2026, 6:24:24 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. 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It allows actors with access to a valid signing key to create multiple valid signatures in order to circumvent TUF requiring a minimum threshold of unique keys before the metadata is considered valid.\n\n### Patches\nThis issue has been addressed in tough version 0.22.0 and tuftool version 0.15.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. \n\n### Workarounds\nNo workarounds to this issue are known.\n\n### References\n* CVE-2026-6966\n\nIf there are any questions or comments about this advisory, please contact [AWS/Amazon] Security via the [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.\n\n### Acknowledgement\n\nAmazon Web Services Labs would like to thank Emily Albini of Oxide Computer and Oleh Konko of 1seal for collaborating on this issue through the coordinated vulnerability disclosure process","state":0,"publishedAt":"2026-05-05T18:46:09+00:00","modifiedAt":"2026-09-10T03:51:04.9950413+00:00","affected":[{"ecosystem":"crates.io","name":"tough","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.22.0"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"crates.io","name":"tuftool","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.15.0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N","score":null,"severity":null},{"system":"CVSS_V4","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","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x","https://nvd.nist.gov/vuln/detail/CVE-2026-6966","https://aws.amazon.com/security/security-bulletins/2026-019-aws","https://crates.io/crates/tough/0.22.0","https://crates.io/crates/tuftool/0.15.0","https://github.com/awslabs/tough","https://github.com/awslabs/tough/releases/tag/tough-v0.22.0","https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0"],"sourceUrl":"https://github.com/advisories/GHSA-8m7c-8m39-rv4x","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-8m7c-8m39-rv4x","identifiers":["GHSA-8m7c-8m39-rv4x","CVE-2026-6966"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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