CVE-2026-6966: AWS tough · Improper Verification of Cryptographic Signature
Affects AWS toughSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.22.0 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.22.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade AWS tough to 0.22.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| AWStough | Affected
| Fixed in– |
| AWStuftool | Affected
| Fixed in– |
crates.iotoughpkg:cargo/toughOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official fix is available. AWS recommends upgrading to tough version 0.22.0 and tuftool version 0.15.0 to remediate this vulnerability. Since this is a client-side library, users should update their deployments accordingly. There is no indication that additional mitigation steps are required beyond applying the official patches.
Description
CVE-2026-6966 is a medium severity vulnerability in AWS tough prior to version 0.22.0. It involves improper verification of cryptographic signature uniqueness during delegated role validation, allowing remote authenticated users to bypass the TUF signature threshold by duplicating a valid signature. This causes the client to accept forged delegated role metadata. AWS has released tough-v0.22.0 and tuftool-v0.15.0 to address this issue.
References
- aws.amazon.com/security/security-bulletins/2026-019-aws/ (opens in a new tab)
- github.com/awslabs/tough/releases/tag/tough-v0.22.0 (opens in a new tab)
- github.com/awslabs/tough/releases/tag/tuftool-v0.15.0 (opens in a new tab)
- crates.io/crates/tough/0.22.0 (opens in a new tab)
- crates.io/crates/tuftool/0.15.0 (opens in a new tab)
- github.com/awslabs/tough/security/advisories/GHSA-8m7c-8m39-rv4x (opens in a new tab)