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Linux Distros Unpatched Vulnerability : CVE-2026-4700

critical Nessus Plugin ID 303539

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.

 - Mitigation bypass in the Networking: HTTP component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. (CVE-2026-4700)

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://access.redhat.com/security/cve/cve-2026-4700

https://security-tracker.debian.org/tracker/CVE-2026-4700

Plugin Details

Severity: Critical

ID: 303539

File Name: unpatched_CVE_2026_4700.nasl

Version: 1.5

Type: local

Agent: unix

Family: Misc.

Published: 3/25/2026

Updated: 3/26/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.5

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

CVSS Score Source: CVE-2026-4700

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9

Vector: CVSS:3.0/AV:N/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, p-cpe:/a:centos:centos:firefox-x11, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:redhat:enterprise_linux:thunderbird-flatpak, p-cpe:/a:redhat:enterprise_linux:firefox-flatpak, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:thunderbird, p-cpe:/a:debian:debian_linux:thunderbird, cpe:/o:centos:centos:8, p-cpe:/a:debian:debian_linux:firefox-esr, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:10, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:centos:centos:firefox, p-cpe:/a:centos:centos:thunderbird-flatpak, p-cpe:/a:redhat:enterprise_linux:firefox-x11, p-cpe:/a:centos:centos:firefox-flatpak, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:centos:centos:thunderbird, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:redhat:enterprise_linux:firefox

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 3/24/2026

Reference Information

CVE: CVE-2026-4700