CVE-2018-12439: Matrixssl

Medium severity, CVSS 4.7. EPSS: 0.3% chance of exploitation in the next 30 days.

MatrixSSL through 3.9.5 Open allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.

Affected products

• Matrixssl Matrixssl: up to and including 3.9.5

Published 2018-06-15. Last modified 2026-06-17.