Use-after-free in Firefox ESR and Mozilla Firefox - CVE-2020-26959

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Main Vulnerability Database Vulnerabilities #VU48464

Use-after-free in Firefox ESR and Mozilla Firefox - CVE-2020-26959

Published: November 17, 2020


Vulnerability identifier: #VU48464
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-2020-26959
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 within the WebRequestService component during browser shutdown. A remote attacker can create a specially crafted web page, trick the victim into visiting it, force the victim to shutdown the browser, 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

Firefox ESR
Mozilla Firefox
Gentoo Linux
Arch Linux
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Scientific Computing
CentOS
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 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
Ubuntu
openEuler
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
thunderbird (Red Hat package)
firefox (Red Hat package)
firefox-esr (Debian package)
thunderbird (Debian package)
firefox (Alpine package)
firefox-esr (Alpine package)
thunderbird (Alpine package)
thunderbird (Ubuntu package)
firefox
firefox-debuginfo
firefox-debugsource
mozilla-crashreporter-firefox-debuginfo
firefox (Ubuntu package)
Mozilla Thunderbird
Firefox for Android

How to mitigate CVE-2020-26959

Install updates from vendor's website.

Firefox ESR - update to 78.5.0
Mozilla Firefox - update to 83.0
Mozilla Thunderbird - update to 78.5.0
thunderbird (Red Hat package) - addressed in versions 78.5.0-1.el6_10, 78.5.0-1.el7_9, 78.5.0-1.el8_0, 78.5.0-1.el8_1, 78.5.0-1.el8_2, 78.5.0-1.el8_3
firefox (Red Hat package) - addressed in versions 78.5.0-1.el6_10, 78.5.0-1.el7_9, 78.5.0-1.el8_0, 78.5.0-1.el8_1, 78.5.0-1.el8_2, 78.5.0-1.el8_3
firefox-esr (Debian package) - update to 78.5.0esr-1~deb10u1
thunderbird (Debian package) - update to 1:78.5.0-1~deb10u1
firefox-esr (Alpine package) - update to 78.5.0-r0
thunderbird (Alpine package) - update to 78.5.1-r0
Firefox for Android - update to 83.0.0
thunderbird (Ubuntu package) - update to 1:78.5.0+build3-0ubuntu0.20.10.1
firefox - update to 79.0-12
firefox-debuginfo - update to 79.0-12
firefox-debugsource - update to 79.0-12
mozilla-crashreporter-firefox-debuginfo - update to 79.0-12
firefox (Ubuntu package) - addressed in versions 83.0+build2-0ubuntu0.16.04.3, 83.0+build2-0ubuntu0.18.04.2, 83.0+build2-0ubuntu0.20.04.1, 83.0+build2-0ubuntu0.20.10.1

External References

Related Security Bulletins