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Linux Distros Unpatched Vulnerability : CVE-2026-63321

critical Nessus Plugin ID 341600

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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.

 - hw/usb/hcd-xhci: Set reentrancy guard in timer functions (CVE-2026-17588) NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/1f24066fc88d33455ee54a20f29994d9e69997ba (v11.1.0-rc3)NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/5fbd2fe1cc54259d045d00d4966aa2db1ba990d6 (v11.0.4) (CVE-2026-18054) NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3917NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/0be94d8d9c28e6b7235b34133d057090fe93be6c (v11.1.0-rc2)NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/88a0e5e45b41d407cf9adf1f2cf6f20f394a578d (v11.0.4) (CVE-2026-50624) NOTE: Fixed by: https://gitlab.com/qemu- project/qemu/-/commit/733a98a552e4bd68932de1f58bd6ea39b57b261c (v11.1.0-rc2)NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/6680c5612401c1eaa49eba134d14d374fefeb9d4 (v11.0.4) (CVE-2026-61402) NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3875NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/f404bf0e6504e0412a00ea64708f17d2a5e3f869 (v11.1.0-rc2)NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/a4abe1f1fa6f465b64fb400bea14c72bd5e32ac9 (v11.0.4) (CVE-2026-61476) NOTE: Fixed by: https://gitlab.com/qemu- project/qemu/-/commit/b9d248dfaca5e31377ea4f7204aae788a050bafd (v11.1.0-rc2)NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/82520d7759557062a5fae2211e3c79bbd5f01ed3 (v11.0.4) (CVE-2026-63110) Host-side AddressSanitizer heap-buffer-overflow READ in current QEMU master through the virtio-net-pci receive filtering path on q35. The crash is in receive_filter(). (CVE-2026-63320) NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/a6e0519ea8ed6fc84fab9bf9ca82c7a55780f880 (v11.1.0-rc2)NOTE: Fixed by: https://gitlab.com/qemu- project/qemu/-/commit/52c7bb369b23dfcafb6e6d90665c777797b55e88 (v11.1.0-rc2)NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/f348425fddae38e0c1d6823501890acfb2a3bfb1 (v11.0.4)NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/9a06bb17256c0a38f0b53025bf804d2e2035f93f (v11.0.4) (CVE-2026-63321) NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3607NOTE: Fixed by:
 https://gitlab.com/qemu-project/qemu/-/commit/4727cc883b7e81d2c30b9801af54482d65b84292 (v11.1.0-rc2)NOTE:
 Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/95b9a1bf26fef7c44f4925f78ade7fa824ed5e76 (v11.0.4) (CVE-2026-63322) virtio-balloon: fix free-page BH teardown on unrealize (CVE-2026-66899) hw/net/virtio- net: strip trailing padding when caching RSC segment (CVE-2026-66900) hw/display/vga: fix text-mode OOB write after a graphics surface switch (CVE-2026-77913) A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management Mode memory. (CVE-2026-81627) io/channel-socket: do not treat a zero length write as an error (CVE-2026-84788) A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest user to craft a fid path containing stale heap data, bypassing directory traversal restrictions and escaping the shared directory boundary. This can lead to arbitrary host file read/write and code execution (VM escape) as the QEMU process user. (CVE-2026-93834) (CVE-2026-63321)

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-2026-63321

https://ubuntu.com/security/CVE-2026-63321

Plugin Details

Severity: Critical

ID: 341600

File Name: unpatched_CVE_2026_63321.nasl

Version: 1.6

Type: Local

Agent: unix

Family: Misc.

Published: 8/30/2026

Updated: 10/29/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.3

Percentile: 10.3

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.3

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

CVSS Score Source: CVE-2026-63321

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 8.3

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.10, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:canonical:ubuntu_linux:qemu-hwe, p-cpe:/a:canonical:ubuntu_linux:qemu, p-cpe:/a:debian:debian_linux:qemu

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

Exploit Ease: No known exploits are available

Reference Information

CVE: CVE-2026-63321