← Fixed vulnerabilities
Fixed
Use-after-free bug in the IPV6_MSFILTER socket option handler
FreeBSD-SA-26:29.ip6_multicast · CVE-2026-49412
Our decision for FreeSense
FreeBSD corrected this on 2026-06-09, before the FreeBSD source pin of every FreeSense version.
- Advisory: corrected 2026-06-09
- FreeSense 1.0 pin: e004ff15f87e (2026-08-03)
- FreeSense 1.1 pin: a52c50b4b7c2 (2026-10-04)
- FreeSense 1.2 pin: a52c50b4b7c2 (2026-10-04)
Decided by rules, not yet reviewed. The status comes from the advisory's correction date and the build configuration. A maintainer has not looked at whether FreeSense is exposed in practice. How we triage
By FreeSense version
| Version | Status | FreeBSD pin |
|---|---|---|
| FreeSense 1.01.0.7 · frozen, no further fixes | FixedFreeBSD pin of 2026-08-03 | 2026-08-03e004ff15 |
| FreeSense 1.11.1.9 | FixedFreeBSD pin of 2026-10-04 | 2026-10-04a52c50b4 |
| FreeSense 1.21.2.0-DEVELOPMENT | FixedFreeBSD pin of 2026-10-04 | 2026-10-04a52c50b4 |
Workaround
No workaround is available.
What FreeBSD says
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.
Impact
An unprivileged local user can exploit this use-after-free to escalate privileges.
Excerpt from the FreeBSD advisory. Read the original for the full text and the fix.