CVE Vulnerabilities


Use After Free

Published: Nov 03, 2020 | Modified: Jul 21, 2021
CVSS 3.x
CVSS 2.x

Use after free in WebRTC in Google Chrome prior to 86.0.4240.75 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.


Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Name Vendor Start Version End Version
Chrome Google * *
Red Hat Enterprise Linux 6 RedHat firefox-0:78.4.0-2.el6_10 *
Red Hat Enterprise Linux 6 RedHat thunderbird-0:78.4.0-1.el6_10 *
Red Hat Enterprise Linux 6 Supplementary RedHat chromium-browser-0:86.0.4240.75-1.el6_10 *
Red Hat Enterprise Linux 7 RedHat firefox-0:78.4.0-1.el7_9 *
Red Hat Enterprise Linux 7 RedHat thunderbird-0:78.4.0-1.el7_9 *
Red Hat Enterprise Linux 8 RedHat firefox-0:78.4.0-1.el8_2 *
Red Hat Enterprise Linux 8 RedHat thunderbird-0:78.4.0-1.el8_3 *
Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions RedHat firefox-0:78.4.0-1.el8_0 *
Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions RedHat thunderbird-0:78.4.0-1.el8_0 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat firefox-0:78.4.0-1.el8_1 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat thunderbird-0:78.4.0-1.el8_1 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat thunderbird-0:78.4.0-1.el8_2 *
Chromium-browser Ubuntu bionic *
Chromium-browser Ubuntu trusty *
Chromium-browser Ubuntu upstream *
Chromium-browser Ubuntu xenial *
Firefox Ubuntu bionic *
Firefox Ubuntu devel *
Firefox Ubuntu esm-infra/xenial *
Firefox Ubuntu focal *
Firefox Ubuntu groovy *
Firefox Ubuntu hirsute *
Firefox Ubuntu impish *
Firefox Ubuntu jammy *
Firefox Ubuntu trusty *
Firefox Ubuntu upstream *
Firefox Ubuntu xenial *
Mozjs52 Ubuntu groovy *
Mozjs68 Ubuntu groovy *
Thunderbird Ubuntu bionic *
Thunderbird Ubuntu devel *
Thunderbird Ubuntu focal *
Thunderbird Ubuntu groovy *
Thunderbird Ubuntu hirsute *
Thunderbird Ubuntu impish *
Thunderbird Ubuntu jammy *
Thunderbird Ubuntu trusty *
Thunderbird Ubuntu upstream *
Thunderbird Ubuntu xenial *

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data chances to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations