Use-after-free in Mozilla Firefox - CVE-2021-23997
Published: April 19, 2021
Vulnerability identifier: #VU52336
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-2021-23997
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a use-after-free error caused by unexpected data type conversions when freeing fonts from cache. A remote attacker can create a specially crafted web page, trick the victim into visiting it, trigger a use-after-free error and execute arbitrary code on the system.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
Affected software
Mozilla Firefox
Arch Linux
Ubuntu
firefox (Ubuntu package)
Arch Linux
Ubuntu
firefox (Ubuntu package)
How to mitigate CVE-2021-23997
Install updates from vendor's website.
Mozilla Firefox - update to 88.0
firefox (Ubuntu package) - addressed in versions 88.0+build2-0ubuntu0.16.04.1, 88.0+build2-0ubuntu0.18.04.2, 88.0+build2-0ubuntu0.20.04.1, 88.0+build2-0ubuntu0.20.10.1, 88.0+build2-0ubuntu0.21.04.1
firefox (Ubuntu package) - addressed in versions 88.0+build2-0ubuntu0.16.04.1, 88.0+build2-0ubuntu0.18.04.2, 88.0+build2-0ubuntu0.20.04.1, 88.0+build2-0ubuntu0.20.10.1, 88.0+build2-0ubuntu0.21.04.1