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FreeBSD : FreeBSD -- Missing large page handling in pmap_pkru_update_range() (128951d0-3df0-11f1-bb07-bc241121aa0a)

medium Nessus Plugin ID 309743

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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 128951d0-3df0-11f1-bb07-bc241121aa0a advisory.

 In order to apply a particular protection key to an address range, the kernel must update the corresponding page table entries.
 The subroutine which handled this failed to take into account the presence of 1GB largepage mappings created using the shm_create_largepage(3) interface. In particular, it would always treat a page directory page entry as pointing to another page table page.
 The bug can be abused by an unprivileged user to cause pmap_pkru_update_range() to treat userspace memory as a page table page, and thus overwrite memory to which the application would otherwise not have access.

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?43ac8564

Plugin Details

Severity: Medium

ID: 309743

File Name: freebsd_pkg_128951d03df011f1bb07bc241121aa0a.nasl

Version: 1.2

Type: Local

Published: 4/22/2026

Updated: 4/24/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

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

CVSS Score Source: CVE-2026-6386

CVSS v3

Risk Factor: Medium

Base Score: 6.2

Temporal Score: 5.4

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

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: Host/local_checks_enabled, Settings/ParanoidReport, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 4/22/2026

Vulnerability Publication Date: 4/22/2026

Reference Information

CVE: CVE-2026-6386

IAVA: 2026-A-0366