CVE-2018-6594: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 2% chance of exploitation in the next 30 days.

lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for PyCrypto's ElGamal implementation.

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 14.04 only; version 16.04 only; version 17.10 only
• Debian Debian Linux: version 7.0 only
• Dlitz Pycrypto: up to and including 2.6.1

Published 2018-02-03. Last modified 2026-06-17.