CVE-2026-49412: Freebsd

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

The kernel handler for IPV6_MSFILTER dropped a serializing lock in order to copy the source-filter list from userspace, then reacquired the lock. During this window another thread could free the multicast filter structure, leaving the handler with a stale pointer to freed memory. An unprivileged local user can exploit this use-after-free to escalate privileges.

Affected products

• Freebsd Freebsd: version 14.3 only; version 14.4 only; version 15.0 only

Published 2026-06-27. Last modified 2026-07-01.