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Linux Distros Unpatched Vulnerability : CVE-2026-4371

high Nessus Plugin ID 303618

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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.

 - A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability affects Thunderbird < 149 and Thunderbird < 140.9. (CVE-2026-4371)

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-2026-4371

https://ubuntu.com/security/CVE-2026-4371

Plugin Details

Severity: High

ID: 303618

File Name: unpatched_CVE_2026_4371.nasl

Version: 1.8

Type: Local

Agent: unix

Family: Misc.

Published: 3/25/2026

Updated: 4/7/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.4

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

CVSS Score Source: CVE-2026-4371

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.8

Vector: CVSS:3.0/AV:N/AC:H/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:20.04:-:lts, p-cpe:/a:redhat:enterprise_linux:thunderbird-flatpak, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:mozjs68, p-cpe:/a:canonical:ubuntu_linux:mozjs38, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:mozjs115, p-cpe:/a:canonical:ubuntu_linux:mozjs91, p-cpe:/a:canonical:ubuntu_linux:mozjs102, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:thunderbird, p-cpe:/a:canonical:ubuntu_linux:mozjs52, p-cpe:/a:canonical:ubuntu_linux:mozjs78, cpe:/o:redhat:enterprise_linux:10

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-2026-4371