CVE-2006-4436: OpenBSD

Medium severity, CVSS 5.0. EPSS: 1.8% chance of exploitation in the next 30 days.

isakmpd in OpenBSD 3.8, 3.9, and possibly earlier versions, creates Security Associations (SA) with a replay window of size 0 when isakmpd acts as a responder during SA negotiation, which allows remote attackers to replay IPSec packets and bypass the replay protection.

Affected products

• OpenBSD OpenBSD: version 3.8 only; version 3.9 only

Published 2006-08-29. Last modified 2026-06-16.