Type Confusion in Mozilla Firefox and Firefox ESR - CVE-2020-15656

Vulnerability identifier: #VU32902

CSH Severity: Medium

CVSS v4: 7.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-15656

CWE-ID: CWE-843

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 type confusion error when JIT optimizations involving the Javascript arguments object could confuse later optimizations in IonMonkey. A remote attacker can pass specially crafted data to the application, trigger a type confusion error and execute arbitrary code on the target system.

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

Mozilla Firefox
Firefox ESR
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_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 IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux Server - TUS
Slackware Linux
Opensuse
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 (Alpine package)
firefox-esr (Alpine package)
firefox (Red Hat package)
firefox (Ubuntu package)
Mozilla Thunderbird

Install updates from vendor's website.

Mozilla Firefox - update to 79.0
Firefox ESR - update to 78.1.0
Mozilla Thunderbird - update to 78.0.1
firefox (Alpine package) - update to 79.0-r0
firefox-esr (Alpine package) - update to 78.1.0-r0
firefox (Red Hat package) - addressed in versions 78.2.0-2.el8_2, 78.2.0-3.el8_0, 78.2.0-3.el8_1, 78.3.0-1.el7_9
firefox (Ubuntu package) - addressed in versions 79.0+build1-0ubuntu0.16.04.2, 79.0+build1-0ubuntu0.18.04.1, 79.0+build1-0ubuntu0.20.04.1

• https://www.mozilla.org/en-US/security/advisories/mfsa2020-30/
• https://www.mozilla.org/en-US/security/advisories/mfsa2020-32/

• Multiple vulnerabilities in Mozilla Firefox
• Multiple vulnerabilities in Mozilla Thunderbird
• OpenSUSE Linux update for MozillaFirefox
• OpenSUSE Linux update for MozillaFirefox
• OpenSUSE Linux update for MozillaFirefox
• Type Confusion in firefox-esr (Alpine package)
• Type Confusion in firefox (Alpine package)
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 7 update for firefox
• Ubuntu update for firefox