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Linux Distros Unpatched Vulnerability : CVE-2026-43249

high Nessus Plugin ID 312797

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - 9p/xen: protect xen_9pfs_front_free against concurrent calls The xenwatch thread can race with other back- end change notifications and call xen_9pfs_front_free() twice, hitting the observed general protection fault due to a double-free. Guard the teardown path so only one caller can release the front-end state at a time, preventing the crash. This is a fix for the following double-free: [ 27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none) [ 27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150 [ 27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 <48> 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42 [ 27.052377] RSP:
 e02b:ffffc9004016fdd0 EFLAGS: 00010246 [ 27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX:
 0000000000000000 [ 27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000 [ 27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000 [ 27.052393] R10:
 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68 [ 27.052397] R13: 0000000000000200 R14:
 0000000000000000 R15: ffff88800a887040 [ 27.052404] FS: 0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000 [ 27.052408] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.052412] CR2:
 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660 [ 27.052418] Call Trace: [ 27.052420] <TASK> [ 27.052422] xen_9pfs_front_changed+0x5d5/0x720 [ 27.052426] ? xenbus_otherend_changed+0x72/0x140 [ 27.052430] ? __pfx_xenwatch_thread+0x10/0x10 [ 27.052434] xenwatch_thread+0x94/0x1c0 [ 27.052438] ?
 __pfx_autoremove_wake_function+0x10/0x10 [ 27.052442] kthread+0xf8/0x240 [ 27.052445] ?
 __pfx_kthread+0x10/0x10 [ 27.052449] ? __pfx_kthread+0x10/0x10 [ 27.052452] ret_from_fork+0x16b/0x1a0 [ 27.052456] ? __pfx_kthread+0x10/0x10 [ 27.052459] ret_from_fork_asm+0x1a/0x30 [ 27.052463] </TASK> [ 27.052465] Modules linked in: [ 27.052471] ---[ end trace 0000000000000000 ]--- (CVE-2026-43249)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://security-tracker.debian.org/tracker/CVE-2026-43249

https://ubuntu.com/security/CVE-2026-43249

Plugin Details

Severity: High

ID: 312797

File Name: unpatched_CVE_2026_43249.nasl

Version: 1.6

Type: Local

Agent: unix

Family: Misc.

Published: 5/6/2026

Updated: 5/25/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

CVSS v2

Risk Factor: Low

Base Score: 1.9

Temporal Score: 1.6

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

CVSS Score Source: CVE-2026-43249

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.1

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:debian:debian_linux:linux, p-cpe:/a:canonical:ubuntu_linux:linux, p-cpe:/a:canonical:ubuntu_linux:linux-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-aws, p-cpe:/a:canonical:ubuntu_linux:linux-azure, p-cpe:/a:canonical:ubuntu_linux:linux-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-gke, p-cpe:/a:canonical:ubuntu_linux:linux-azure-edge, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-raspi, p-cpe:/a:canonical:ubuntu_linux:linux-oem, p-cpe:/a:canonical:ubuntu_linux:linux-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-aws-hwe, p-cpe:/a:canonical:ubuntu_linux:linux-bluefield, p-cpe:/a:canonical:ubuntu_linux:linux-ibm, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-gke-5.15, cpe:/o:debian:debian_linux:12.0, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-azure-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-hwe, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-intel-iotg, p-cpe:/a:canonical:ubuntu_linux:linux-intel-iotg-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-iot, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-raspi-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-riscv, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-xilinx-zynqmp, p-cpe:/a:canonical:ubuntu_linux:linux-gkeop-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-edge, p-cpe:/a:canonical:ubuntu_linux:linux-ibm-5.4, p-cpe:/a:canonical:ubuntu_linux:linux-ibm-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-intel-iot-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-lts-xenial, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-raspi-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-realtime, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-gke-4.15, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.6, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.0, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-tegra, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-tegra-igx, p-cpe:/a:canonical:ubuntu_linux:linux-allwinner-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-intel-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-azure-nvidia, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.3, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-aws-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-azure-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.11, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-ibm-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-5.19, p-cpe:/a:canonical:ubuntu_linux:linux-lowlatency-hwe-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-tegra-5.15, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.10, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.14, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.17, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.0, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.1, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.8, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-5.11, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.5, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-starfive-6.2, p-cpe:/a:canonical:ubuntu_linux:linux-oem-5.13, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.11, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-azure-nvidia-6.14, p-cpe:/a:canonical:ubuntu_linux:linux-xilinx, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.8, p-cpe:/a:canonical:ubuntu_linux:linux-oem-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-aws-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-gcp-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-hwe-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-oracle-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-riscv-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-azure-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-azure-fde-6.17, p-cpe:/a:canonical:ubuntu_linux:linux-nvidia-6.17

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 5/6/2026

Reference Information

CVE: CVE-2026-43249