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FreeBSD : FreeBSD -- Remote code execution via RPCSEC_GSS packet validation (733febba-28d2-11f1-b35e-bc241121aa0a)

high Nessus Plugin ID 303908

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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 733febba-28d2-11f1-b35e-bc241121aa0a advisory.

 Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet. This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow. Notably, this does not require the client to authenticate itself first.
 As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel.
 In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system.

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?7b55fac3

Plugin Details

Severity: High

ID: 303908

File Name: freebsd_pkg_733febba28d211f1b35ebc241121aa0a.nasl

Version: 1.2

Type: Local

Published: 3/26/2026

Updated: 4/13/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9.2

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-4747

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.4

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

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

Vulnerability Information

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

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/26/2026

Vulnerability Publication Date: 3/26/2026

Reference Information

CVE: CVE-2026-4747