RHEL 9 : firefox (RHSA-2026:21378)

critical Nessus Plugin ID 317375

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Synopsis

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

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:21378 advisory.

Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.

Security Fix(es):

* firefox: Incorrect boundary conditions in the JavaScript Engine: JIT component (CVE-2026-8388)

* firefox: Other issue in the JavaScript Engine component (CVE-2026-8391)

* firefox: Sandbox escape in the Profile Backup component (CVE-2026-8401)

* firefox: Integer overflow in the Networking: JAR component (CVE-2026-8956)

* firefox: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151 (CVE-2026-8975)

* firefox: Privilege escalation in the DOM: Workers component (CVE-2026-8955)

* firefox: Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component (CVE-2026-8968)

* firefox: Incorrect boundary conditions, integer overflow in the Audio/Video component (CVE-2026-8954)

* firefox: Information disclosure, sandbox escape in the Security: Process Sandboxing component (CVE-2026-8958)

* firefox: Incorrect boundary conditions in the Audio/Video: Web Codecs component (CVE-2026-8946)

* firefox: Privilege escalation in the Security component (CVE-2026-8970)

* firefox: Same-origin policy bypass in the Networking: HTTP component (CVE-2026-8950)

* firefox: Memory safety bugs fixed in Firefox ESR 140.11 and Firefox 151 (CVE-2026-8974)

* firefox: Sandbox escape due to use-after-free in the Disability Access APIs component (CVE-2026-8953)

* firefox: Spoofing issue in the Form Autofill component (CVE-2026-8961)

* firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-8947)

* firefox: Mitigation bypass in the DOM: Security component (CVE-2026-8962)

* firefox: Privilege escalation in the Enterprise Policies component (CVE-2026-8957)

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 firefox package based on the guidance in RHSA-2026:21378.

Plugin Details

Severity: Critical

ID: 317375

File Name: redhat-RHSA-2026-21378.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 5/28/2026

Updated: 5/28/2026

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

Risk Information

VPR

Risk Factor: High

Score: 7.3

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-8975

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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:O/RC:C

CVSS Score Source: CVE-2026-8956

Vulnerability Information

CPE: cpe:/o:redhat:rhel_eus:9.8, p-cpe:/a:redhat:enterprise_linux:firefox, p-cpe:/a:redhat:enterprise_linux:firefox-x11, cpe:/o:redhat:enterprise_linux:9

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/27/2026

Vulnerability Publication Date: 5/12/2026

Reference Information

CVE: CVE-2026-8388, CVE-2026-8391, CVE-2026-8401, CVE-2026-8946, CVE-2026-8947, CVE-2026-8950, CVE-2026-8953, CVE-2026-8954, CVE-2026-8955, CVE-2026-8956, CVE-2026-8957, CVE-2026-8958, CVE-2026-8961, CVE-2026-8962, CVE-2026-8968, CVE-2026-8970, CVE-2026-8974, CVE-2026-8975

CWE: 190, 266, 358, 403, 472, 475, 653, 787, 825

RHSA: 2026:21378

Detections

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