Information disclosure in Mozilla Firefox and Firefox ESR - CVE-2021-23973

Vulnerability identifier: #VU50888

CSH Severity: Low

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:Clear

CVE-ID: CVE-2021-23973

CWE-ID: CWE-200

Exploitation vector: Remote access

Exploit availability: No public exploit available

Affected software:
Mozilla Firefox
Firefox ESR
Gentoo Linux
SUSE CaaS Platform
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Enterprise Storage
Red Hat Enterprise Linux Server
CentOS
SUSE OpenStack Cloud
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 for x86_64
Red Hat Enterprise Linux for ARM 64
SUSE OpenStack Cloud Crowbar
HPE Helion Openstack
Red Hat Enterprise Linux for x86_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 ARM 64 - Extended Update Support
Red Hat Enterprise Linux Server - TUS
SUSE Linux Enterprise Debuginfo
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise Software Development Kit
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Workstation Extension
SUSE Linux Enterprise Module for Desktop Applications
Ubuntu
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
firefox-esr (Debian package)
firefox-esr (Alpine package)
thunderbird (Debian package)
firefox (Red Hat package)
thunderbird (Red Hat package)
MozillaFirefox-translations-other
MozillaFirefox-translations-common
MozillaFirefox-devel
MozillaFirefox-debugsource
MozillaFirefox-debuginfo
MozillaFirefox
MozillaThunderbird-debuginfo
MozillaThunderbird-debugsource
MozillaThunderbird-translations-common
MozillaThunderbird-translations-other
MozillaThunderbird
thunderbird (Ubuntu package)
firefox (Ubuntu package)
Mozilla Thunderbird

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

The vulnerability exists due to excessive data output via a decoding error, when trying to load a cross-origin resource in an audio/video context. A remote attacker can gain access to information about the resource.

Install updates from vendor's website.

• https://www.mozilla.org/en-US/security/advisories/mfsa2021-07/
• https://www.mozilla.org/en-US/security/advisories/mfsa2021-08/