Use After Free in FreeBSD

CVE-2026-49412

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.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (3.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 3.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-49412: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

  • FreeBSD — versions 14.3, 15.0, 14.4-RELEASE

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-49412?
CVE-2026-49412 is a high-severity vulnerability in FreeBSD, classified under Use After Free. CVSS score: 7.8/10. Published 2026-06-27.
How severe is CVE-2026-49412?
High severity. CVSS v3 base score is 7.8 out of 10.