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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 4.0
- 7.0 HIGHCVSS: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/M
- EPSS
- 0.26% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Affected
- amazon/tough · amazon/tuftool
- Source
- ff89ba41-3aa1-4d27-914a-91399e9639e5
References
- https://aws.amazon.com/security/security-bulletins/2026-019-aws/Vendor Advisory
- https://crates.io/crates/tough/0.22.0Product
- https://crates.io/crates/tuftool/0.15.0Product
- https://github.com/awslabs/tough/releases/tag/tough-v0.22.0Release Notes
- https://github.com/awslabs/tough/releases/tag/tuftool-v0.15.0Release Notes
- https://github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4xVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.