CVE-2017-12972: CONNECT2ID Nimbus Jose+jwt

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

In Nimbus JOSE+JWT before 4.39, there is no integer-overflow check when converting length values from bytes to bits, which allows attackers to conduct HMAC bypass attacks by shifting Additional Authenticated Data (AAD) and ciphertext so that different plaintext is obtained for the same HMAC.

Affected products

• CONNECT2ID Nimbus Jose+jwt: version 1.0 only; version 1.1 only; version 1.2 only; version 1.3 only; version 1.4 only; version 1.5 only; …

Published 2017-08-20. Last modified 2026-06-17.