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.
Advisories

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Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Mon, 29 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Sat, 27 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Freebsd
Freebsd freebsd
Vendors & Products Freebsd
Freebsd freebsd

Sat, 27 Jun 2026 09:15:00 +0000

Type Values Removed Values Added
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.
Title Use-after-free bug in the IPV6_MSFILTER socket option handler
Weaknesses CWE-416
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: freebsd

Published:

Updated: 2026-06-30T03:55:29.049Z

Reserved: 2026-05-29T20:24:28.615Z

Link: CVE-2026-49412

cve-icon Vulnrichment

Updated: 2026-06-29T13:06:20.730Z

cve-icon NVD

Status : Analyzed

Published: 2026-06-27T09:16:23.937

Modified: 2026-07-01T14:04:44.963

Link: CVE-2026-49412

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-29T14:45:04Z

Weaknesses