How severe is CVE-2026-6966?

CVE-2026-6966 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-6966 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6966?

CVE-2026-6966 primarily affects Amazon Tough. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-6966?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-6966 have an EU (EUVD) identifier?

Yes. CVE-2026-6966 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25627.

When was CVE-2026-6966 published?

CVE-2026-6966 was published on 2026-04-24 and last updated on 2026-06-17.

CVE-2026-6966

CVE-2026-6966 is a medium-severity vulnerability in Amazon Tough with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 7.0
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-25627
Weakness: CWE-347
Affected product: Amazon Tough
Published: 2026-04-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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 the client to accept forged delegated role metadata. We recommend you upgrade to tough-v0.22.0 / tuftool-v0.15.0.
How severe is CVE-2026-6966?: CVE-2026-6966 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-6966 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6966?: CVE-2026-6966 primarily affects Amazon Tough. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-6966?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-6966 have an EU (EUVD) identifier?: Yes. CVE-2026-6966 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-25627.
When was CVE-2026-6966 published?: CVE-2026-6966 was published on 2026-04-24 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:amazon:tough:*:*:*:*:*:rust:*:*
cpe:2.3:a:amazon:tuftool:*:*:*:*:*:rust:*:*

More vulnerabilities in Amazon Tough

CVE-2020-15093 — High (CVSS 8.6): The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic…
CVE-2021-41150 — High (CVSS 8.2): Tough provides a set of Rust libraries and tools for using and generating the update framework (TUF) repositories. The…
CVE-2021-41149 — High (CVSS 8.2): Tough provides a set of Rust libraries and tools for using and generating the update framework (TUF) repositories. The…
CVE-2026-6968 — Medium (CVSS 5.9): Incomplete path traversal fixes in awslabs/tough before tough-v0.22.0 allow remote authenticated users with delegated…
CVE-2026-6967 — Medium (CVSS 5.9): Missing expiration, hash, and length enforcement in delegated metadata validation in awslabs/tough before tough-v0.22.0…
CVE-2025-2888 — Medium (CVSS 4.5): During a snapshot rollback, the client incorrectly caches the timestamp metadata. If the client checks the cache when…

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