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FreeBSD : FreeBSD -- Use-after-free in TCP RACK stack option handler (6c547c1b-74e2-11f1-958d-bc241121aa0a)

high Nessus Plugin ID 324130

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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 6c547c1b-74e2-11f1-958d-bc241121aa0a advisory.

 The RACK setsockopt(2) handler drops the connection lock in order to copy option data from userspace, then reacquires the lock.
 After reacquiring, it verifies that the TCP stack had not been switched away, but did not reload its pointer to the stack's per-connection control block. If userspace switches stacks twice during this window, the check will succeed but the saved pointer will refer to freed memory.
 The bug may be exploitable by an unprivileged local user 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?784e4864

Plugin Details

Severity: High

ID: 324130

File Name: freebsd_pkg_6c547c1b74e211f1958dbc241121aa0a.nasl

Version: 1.2

Type: Local

Published: 7/1/2026

Updated: 8/24/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.17

CVSS v3

Risk Factor: High

Base Score: 8.4

Temporal Score: 7.3

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

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

CVSS Score Source: CVE-2026-49422

Vulnerability Information

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

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/1/2026

Vulnerability Publication Date: 7/1/2026

Reference Information

CVE: CVE-2026-49422