Detections
Analytics

FreeBSD : FreeBSD -- Use-after-free bug in the IPV6_MSFILTER socket option handler (c5b7ac13-6473-11f1-958d-bc241121aa0a)

high Nessus Plugin ID 320474

Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the c5b7ac13-6473-11f1-958d-bc241121aa0a advisory.

 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.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

http://www.nessus.org/u?c6fcb2f2

Plugin Details

Severity: High

ID: 320474

File Name: freebsd_pkg_c5b7ac13647311f1958dbc241121aa0a.nasl

Version: 1.1

Type: Local

Published: 6/11/2026

Updated: 6/11/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 4.5

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:C/A:P

CVSS Score Source: CVE-2026-49412

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:freebsd-kernel, cpe:/o:freebsd:freebsd

Required KB Items: Settings/ParanoidReport, Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 6/10/2026

Vulnerability Publication Date: 6/10/2026

Reference Information

CVE: CVE-2026-49412