Buffer overflow in Firefox ESR and Mozilla Firefox - CVE-2021-23964

Vulnerability identifier: #VU50025

CSH Severity: High

CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-23964

CWE-ID: CWE-119

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing HTML content. A remote attacker can create a specially crafted website, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Firefox ESR
Mozilla Firefox
Gentoo Linux
Arch Linux
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux Server - TUS
Ubuntu
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
firefox-esr (Alpine package)
thunderbird (Debian package)
firefox-esr (Debian package)
firefox (Red Hat package)
thunderbird (Red Hat package)
thunderbird (Alpine package)
mozjs78 (Alpine package)
thunderbird (Ubuntu package)
firefox (Ubuntu package)
Mozilla Thunderbird

Install updates from vendor's website.

Firefox ESR - update to 78.7.0
Mozilla Firefox - update to 85.0
Mozilla Thunderbird - update to 78.7.0
firefox-esr (Alpine package) - update to 78.7.0-r0
thunderbird (Debian package) - update to 78.7.0-1~deb10u1
firefox-esr (Debian package) - update to 78.7.0esr-1~deb10u1
firefox (Red Hat package) - addressed in versions 78.7.0-2.el7_9, 78.7.0-2.el8_1, 78.7.0-2.el8_2, 78.7.0-2.el8_3
thunderbird (Red Hat package) - addressed in versions 78.7.0-1.el7_9, 78.7.0-1.el8_1, 78.7.0-1.el8_2, 78.7.0-1.el8_3
thunderbird (Alpine package) - update to 78.7.0-r0
mozjs78 (Alpine package) - update to 78.7.0-r0
thunderbird (Ubuntu package) - update to 1:78.7.1+build1-0ubuntu0.20.10.4
firefox (Ubuntu package) - addressed in versions 85.0+build1-0ubuntu0.16.04.1, 85.0+build1-0ubuntu0.18.04.1, 85.0+build1-0ubuntu0.20.04.1, 85.0+build1-0ubuntu0.20.10.1

• https://www.mozilla.org/en-US/security/advisories/mfsa2021-03/
• https://www.mozilla.org/en-US/security/advisories/mfsa2021-04/

• Multiple vulnerabilities in Mozilla Firefox and Firefox ESR
• Multiple vulnerabilities in Mozilla Thunderbird
• Red Hat Enterprise Linux 8.1 update for firefox
• Buffer overflow in firefox-esr (Alpine package)
• Buffer overflow in mozjs78 (Alpine package)
• Debian update for firefox-esr
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 8.2 update for thunderbird
• Red Hat Enterprise Linux 7 update for firefox
• Red Hat Enterprise Linux 8.2 update for firefox
• Red Hat Enterprise Linux 7 update for thunderbird
• Red Hat Enterprise Linux 8 update for thunderbird
• Gentoo update for Mozilla Thunderbird
• Debian update for thunderbird
• Gentoo update for Mozilla Firefox
• Arch Linux update for firefox
• Arch Linux update for thunderbird
• Red Hat Enterprise Linux 8.1 update for thunderbird
• Buffer overflow in thunderbird (Alpine package)
• Ubuntu update for firefox
• Ubuntu update for thunderbird