RHEL 9 : firefox (RHSA-2026:99111)

critical Nessus Plugin ID 379517

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-2026:99111 advisory.

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

Security Fix(es):

* firefox: thunderbird: Use-after-free in the JavaScript: GC component (CVE-2026-118007)

* firefox: thunderbird: Sandbox escape due to use-after-free in the XPCOM component (CVE-2026-118021)

* firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-118024)

* firefox: thunderbird: Race condition, use-after-free in the DOM: File component (CVE-2026-118019)

* firefox: thunderbird: Use-after-free in the Audio/Video component (CVE-2026-124860)

* firefox: thunderbird: Site isolation issue in the DOM: Navigation component (CVE-2026-124914)

* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-124869)

* firefox: thunderbird: Privilege escalation in the DOM: Navigation component (CVE-2026-124854)

* firefox: thunderbird: Use-after-free in the Layout: Positioned component (CVE-2026-124877)

* firefox: thunderbird: Sandbox escape due to use-after-free in the Widget: Gtk component (CVE-2026-124917)

* firefox: thunderbird: Incorrect boundary conditions in the DOM: Selection component (CVE-2026-124891)

* firefox: thunderbird: Use-after-free in the Graphics: Canvas2D component (CVE-2026-124857)

* firefox: thunderbird: Information disclosure in the Security: RLBox component (CVE-2026-124941)

* firefox: thunderbird: Sandbox escape in the DOM: Navigation component (CVE-2026-124855)

* firefox: thunderbird: Spoofing issue in the Security component (CVE-2026-124934)

* firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Graphics: Text component (CVE-2026-124853)

* firefox: thunderbird: Sandbox escape in the DOM: Navigation component (CVE-2026-124905)

* firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Storage: Cache API component (CVE-2026-124859)

* firefox: thunderbird: Use-after-free in the CSS Parsing and Computation component (CVE-2026-124881)

* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-124862)

* firefox: thunderbird: Use-after-free in the CSS Parsing and Computation component (CVE-2026-124882)

* firefox: thunderbird: Information disclosure in the Private Browsing component (CVE-2026-124909)

* firefox: thunderbird: Use-after-free in the CSS Parsing and Computation component (CVE-2026-124876)

* firefox: thunderbird: Use-after-free in the DOM: Workers component (CVE-2026-124893)

* firefox: thunderbird: Use-after-free in the Graphics: WebRender component (CVE-2026-124906)

* firefox: thunderbird: Incorrect boundary conditions in the Layout: Text and Fonts component (CVE-2026-124887)

* firefox: thunderbird: Mitigation bypass in the WebExtensions component (CVE-2026-124910)

* firefox: thunderbird: Privilege escalation in the Nimbus Desktop Client component (CVE-2026-124951)

* firefox: thunderbird: Use-after-free in the Audio/Video component (CVE-2026-124865)

* firefox: thunderbird: Incorrect boundary conditions, use-after-free in the Graphics component (CVE-2026-124948)

* firefox: thunderbird: Undefined behavior in the WebRTC: Networking component (CVE-2026-124935)

* firefox: thunderbird: Incorrect boundary conditions in the DOM: CSS Object Model component (CVE-2026-124875)

* firefox: thunderbird: Sandbox escape due to use-after-free in the IPC component (CVE-2026-124903)

* firefox: thunderbird: Incorrect boundary conditions in the Networking: HTTP component (CVE-2026-124856)

* firefox: thunderbird: Use-after-free in the Networking: Cookies component (CVE-2026-124894)

* firefox: thunderbird: Use-after-free in the Storage: localStorage & sessionStorage component (CVE-2026-124895)

* firefox: thunderbird: Use-after-free in the Graphics: Text component (CVE-2026-124885)

* firefox: thunderbird: Use-after-free in the Layout: Text and Fonts component (CVE-2026-124899)

* firefox: thunderbird: Sandbox escape in the Console component (CVE-2026-124933)

* firefox: thunderbird: Use-after-free in the Layout component (CVE-2026-124866)

* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-124883)

* firefox: thunderbird: Information disclosure in the Layout: Form Controls component (CVE-2026-124929)

* firefox: thunderbird: Incorrect boundary conditions in the JavaScript: GC component (CVE-2026-124870)

* firefox: thunderbird: Site isolation issue in the Graphics: WebRender component (CVE-2026-124927)

* firefox: thunderbird: Incorrect boundary conditions in the Graphics: WebGPU component (CVE-2026-124915)

* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-124890)

* firefox: thunderbird: Information disclosure in the Address Bar component (CVE-2026-124930)

* firefox: thunderbird: Invalid pointer in the Layout: Text and Fonts component (CVE-2026-124886)

* firefox: thunderbird: Use-after-free in the DOM: HTML Parser component (CVE-2026-124858)

* firefox: thunderbird: Privilege escalation, sandbox escape due to use-after-free in the Graphics:
CanvasWebGL component (CVE-2026-124907)

* firefox: thunderbird: Invalid pointer in the DOM: Editor component (CVE-2026-124873)

* firefox: thunderbird: Spoofing issue in the DOM: Security component (CVE-2026-124912)

* firefox: thunderbird: Same-origin policy bypass in the Networking: HTTP component (CVE-2026-124874)

* firefox: thunderbird: Use-after-free in the JavaScript: GC component (CVE-2026-124892)

* firefox: thunderbird: Invalid pointer in the DOM: Streams component (CVE-2026-124942)

* firefox: thunderbird: Use-after-free in the CSS Transitions and Animations component (CVE-2026-124922)

* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics:
WebRender component (CVE-2026-124918)

* firefox: thunderbird: Use-after-free in the JavaScript: GC component (CVE-2026-124884)

* firefox: thunderbird: Incorrect boundary conditions in the DOM: Core & HTML component (CVE-2026-124868)

* firefox: thunderbird: Privilege escalation due to use-after-free in the WebRTC: Networking component (CVE-2026-124919)

* firefox: thunderbird: Incorrect boundary conditions in the Graphics: WebRender component (CVE-2026-124924)

* firefox: thunderbird: Same-origin policy bypass due to race condition in the Audio/Video component (CVE-2026-124902)

* firefox: thunderbird: Invalid pointer in the Networking: Cache component (CVE-2026-124879)

* firefox: thunderbird: Use-after-free in the Graphics component (CVE-2026-124932)

* firefox: thunderbird: Mitigation bypass in the File Handling component (CVE-2026-124940)

* firefox: thunderbird: Same-origin policy bypass in the DOM: Core & HTML component (CVE-2026-124931)

* firefox: thunderbird: Incorrect boundary conditions in the WebRTC component (CVE-2026-124926)

* firefox: thunderbird: Use-after-free in the DOM: HTML Parser component (CVE-2026-124863)

* firefox: thunderbird: Use-after-free in the CSS Parsing and Computation component (CVE-2026-124889)

* firefox: thunderbird: Site isolation issue in the Networking component (CVE-2026-124913)

* firefox: thunderbird: Use-after-free in the JavaScript: GC component (CVE-2026-124897)

* firefox: thunderbird: Sandbox escape due to use-after-free in the DOM: Service Workers component (CVE-2026-124864)

* firefox: thunderbird: Use-after-free in the Cycle Collector component (CVE-2026-124872)

* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-124880)

* firefox: thunderbird: Invalid pointer in the Layout: Text and Fonts component (CVE-2026-124896)

* firefox: thunderbird: Other issue in the Networking: JAR component (CVE-2026-124901)

* firefox: thunderbird: Incorrect boundary conditions in the Layout: Text and Fonts component (CVE-2026-124888)

* firefox: thunderbird: Mitigation bypass in the Add-ons Manager component (CVE-2026-124938)

* firefox: thunderbird: Sandbox escape due to use-after-free in the Audio/Video: cubeb component (CVE-2026-124861)

* firefox: thunderbird: Use-after-free in the DOM: Editor component (CVE-2026-124898)

* firefox: thunderbird: JIT miscompilation in the JavaScript Engine: JIT component (CVE-2026-124939)

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-2026:99111.

Plugin Details

Severity: Critical

ID: 379517

File Name: redhat-RHSA-2026-99111.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 11/12/2026

Updated: 11/12/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.31

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-2026-124948

CVSS v3

Risk Factor: Critical

Base Score: 9.6

Temporal Score: 8.3

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

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

CVSS Score Source: CVE-2026-124917

Vulnerability Information

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

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: 11/11/2026

Vulnerability Publication Date: 10/27/2026

Reference Information

CVE: CVE-2026-118007, CVE-2026-118019, CVE-2026-118021, CVE-2026-118024, CVE-2026-124853, CVE-2026-124854, CVE-2026-124855, CVE-2026-124856, CVE-2026-124857, CVE-2026-124858, CVE-2026-124859, CVE-2026-124860, CVE-2026-124861, CVE-2026-124862, CVE-2026-124863, CVE-2026-124864, CVE-2026-124865, CVE-2026-124866, CVE-2026-124868, CVE-2026-124869, CVE-2026-124870, CVE-2026-124872, CVE-2026-124873, CVE-2026-124874, CVE-2026-124875, CVE-2026-124876, CVE-2026-124877, CVE-2026-124879, CVE-2026-124880, CVE-2026-124881, CVE-2026-124882, CVE-2026-124883, CVE-2026-124884, CVE-2026-124885, CVE-2026-124886, CVE-2026-124887, CVE-2026-124888, CVE-2026-124889, CVE-2026-124890, CVE-2026-124891, CVE-2026-124892, CVE-2026-124893, CVE-2026-124894, CVE-2026-124895, CVE-2026-124896, CVE-2026-124897, CVE-2026-124898, CVE-2026-124899, CVE-2026-124901, CVE-2026-124902, CVE-2026-124903, CVE-2026-124905, CVE-2026-124906, CVE-2026-124907, CVE-2026-124909, CVE-2026-124910, CVE-2026-124912, CVE-2026-124913, CVE-2026-124914, CVE-2026-124915, CVE-2026-124917, CVE-2026-124918, CVE-2026-124919, CVE-2026-124922, CVE-2026-124924, CVE-2026-124926, CVE-2026-124927, CVE-2026-124929, CVE-2026-124930, CVE-2026-124931, CVE-2026-124932, CVE-2026-124933, CVE-2026-124934, CVE-2026-124935, CVE-2026-124938, CVE-2026-124939, CVE-2026-124940, CVE-2026-124941, CVE-2026-124942, CVE-2026-124948, CVE-2026-124951

CWE: 193, 266, 270, 290, 346, 359, 475, 497, 653, 763, 787, 807, 825, 843, 939

RHSA: 2026:99111

Detections

Analytics