RHEL 9 : thunderbird (RHSA-2026:8459)

critical Nessus Plugin ID 306764

Synopsis

The remote Red Hat host is missing one or more security updates for thunderbird.

Description

The remote Redhat Enterprise Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:8459 advisory.

Mozilla Thunderbird is a standalone mail and newsgroup client.

Security Fix(es):

* libpng: libpng: Arbitrary code execution due to use-after-free vulnerability (CVE-2026-33416)

* libpng: libpng: Information disclosure and denial of service via out-of-bounds read/write in Neon palette expansion (CVE-2026-33636)

* thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5734)

* thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5731)

* firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics: Text component (CVE-2026-5732)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL thunderbird package based on the guidance in RHSA-2026:8459.

See Also

https://access.redhat.com/security/updates/classification/#important

https://bugzilla.redhat.com/show_bug.cgi?id=2451805

https://bugzilla.redhat.com/show_bug.cgi?id=2451819

https://bugzilla.redhat.com/show_bug.cgi?id=2455897

https://bugzilla.redhat.com/show_bug.cgi?id=2455901

https://bugzilla.redhat.com/show_bug.cgi?id=2455908

http://www.nessus.org/u?f794e9f0

https://access.redhat.com/errata/RHSA-2026:8459

Plugin Details

Severity: Critical

ID: 306764

File Name: redhat-RHSA-2026-8459.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 4/16/2026

Updated: 4/16/2026

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

Risk Information

VPR

Risk Factor: High

Score: 7.4

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-5734

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:thunderbird, cpe:/o:redhat:enterprise_linux:9

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/16/2026

Vulnerability Publication Date: 3/10/2026

Reference Information

CVE: CVE-2026-33416, CVE-2026-33636, CVE-2026-5731, CVE-2026-5732, CVE-2026-5734

CWE: 124, 190, 787, 825

RHSA: 2026:8459