CVE-2016-8858: OpenBSD OpenSSH

High severity, CVSS 7.5. EPSS: 29.5% chance of exploitation in the next 30 days.

The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that "OpenSSH upstream does not consider this as a security issue."

Affected products

• OpenBSD OpenSSH: version 6.8 only; version 6.9 only; version 7.0 only; version 7.1 only; version 7.2 only; version 7.3 only

Published 2016-12-09. Last modified 2026-06-17.