Out-of-bounds read in Mozilla Firefox - CVE-2020-6821

Vulnerability identifier: #VU26649

CSH Severity: Medium

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

CVE-ID: CVE-2020-6821

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

Affected software:
Mozilla Firefox
Firefox ESR
Gentoo Linux
Arch Linux
Red Hat Enterprise Linux for IBM z Systems
CentOS
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Slackware Linux
Opensuse
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 (Ubuntu package)
firefox-esr (Debian package)
thunderbird (Debian package)
firefox (Alpine package)
thunderbird (Red Hat package)
firefox-esr (Alpine package)
firefox (Red Hat package)
thunderbird (Ubuntu package)
mozjs68 (Alpine package)
thunderbird (Alpine package)
Mozilla Thunderbird

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition when using WebGL copyTexSubImage method. A remote attacker can create a specially crafted web page, trick the victim into opening it, trigger out-of-bounds read error and read contents of uninitialized memory on the system.

Install updates from vendor's website.

• https://www.mozilla.org/en-US/security/advisories/mfsa2020-12/