Vulnerability · Published Jun 27, 2026 · Assigned by freebsd
CVE-2026-49412Use-after-free bug in the IPV6_MSFILTER socket option handler
High 7.8
In plain English
A high-severity use-after-free in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).
Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 95.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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 (as reported)
Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H