CVE-2026-6966: Improper verification of cryptographic signature uniqueness in delegated role validation in awslabs/tough befo

Q: How do I fix CVE-2026-6966?

tough: upgrade to 0.22.0; tuftool: upgrade to 0.15.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-6966 being exploited?

CVE-2026-6966 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-6966 affect?

CVE-2026-6966 affects tough, tuftool. Severity is medium (CVSS 5.3). 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

Q: How urgent is CVE-2026-6966?

Priority 29/100. On your watchlist

Routine

MEDIUM 5.3WATCHLISTUPGRADEUPGRADE

CVE-2026-6966 is a medium-severity flaw (CVSS 5.3) affecting tough, tuftool. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-347
Published	2026-04-24
Last modified	2026-10-26

Publisher (CNA): AMZN · Vendor: amazon

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-24 20:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

amazon tough UPGRADE

Affected: < 0.22.0

Fixed in: 0.22.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tough || rpm -q tough || tough --version

2. UPGRADE to 0.22.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tough

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tough

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

amazon tuftool UPGRADE

Affected: < 0.15.0

Fixed in: 0.15.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tuftool || rpm -q tuftool || tuftool --version

2. UPGRADE to 0.15.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tuftool

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tuftool

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-6966?

tough: upgrade to 0.22.0; tuftool: upgrade to 0.15.0. Exact commands for each OS are on this page.

Is CVE-2026-6966 being exploited?

CVE-2026-6966 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-6966 affect?

CVE-2026-6966 affects tough, tuftool. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2026-6966?

Priority 29/100. On your watchlist

Related CVEs

CVE-2026-6968 MEDIUM 5.9 UPGRADE UPGRADE Incomplete path traversal fixes in awslabs/tough before tough-v0.22.0 allow remote authenticated users with de
CVE-2026-6967 MEDIUM 5.9 UPGRADE UPGRADE Missing expiration, hash, and length enforcement in delegated metadata validation in awslabs/tough before toug

References

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