Security Vulnerability Report
中文
CVE-2026-6966 CVSS 5.3 MEDIUM

CVE-2026-6966

Published: 2026-04-24 20:16:29
Last Modified: 2026-05-06 15:24:57
Source: ff89ba41-3aa1-4d27-914a-91399e9639e5

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. We recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.

CVSS Details

CVSS Score
5.3
Severity
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

Configurations (Affected Products)

cpe:2.3:a:amazon:tough:*:*:*:*:*:rust:*:* - VULNERABLE
cpe:2.3:a:amazon:tuftool:*:*:*:*:*:rust:*:* - VULNERABLE
awslabs/tough < tough-v0.22.0
awslabs/tuftool < tuftool-v0.15.0

PoC / Exploit Code

⚠ For Security Research Only
The following code is for security research and authorized testing only.
python
{ "signed": { "_type": "targets", "version": 1, "expires": "2026-12-31T00:00:00Z", "targets": {} }, "signatures": [ { "keyid": "valid_key_id_1", "sig": "valid_signature_hash_1" }, // Exploit: Duplicating the same signature to bypass the threshold requirement { "keyid": "valid_key_id_1", "sig": "valid_signature_hash_1" } ] }

References

Raw JSON Data

JSON
{"cve": {"id": "CVE-2026-6966", "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "published": "2026-04-24T20:16:28.883", "lastModified": "2026-05-06T15:24:56.720", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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\nWe recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0."}], "metrics": {"cvssMetricV40": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "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", "baseScore": 7.0, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.6, "impactScore": 3.6}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-347"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:amazon:tough:*:*:*:*:*:rust:*:*", "versionEndExcluding": "0.22.0", "matchCriteriaId": "B861C5C6-71EB-48B0-B55E-71BBF56DF2BF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:amazon:tuftool:*:*:*:*:*:rust:*:*", "versionEndExcluding": "0.15.0", "matchCriteriaId": "E83215AA-4B4B-44C1-A062-B7212CF33EF5"}]}]}], "references": [{"url": "https://aws.amazon.com/security/security-bulletins/2026-019-aws/", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Vendor Advisory"]}, {"url": "https://crates.io/crates/tough/0.22.0", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Product"]}, {"url": "https://crates.io/crates/tuftool/0.15.0", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Product"]}, {"url": "https://github.com/awslabs/tough/releases/tag/tough-v0.22.0", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Release Notes"]}, {"url": "https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Release Notes"]}, {"url": "https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "tags": ["Vendor Advisory"]}]}}