CVE-2020-6814: Critical severity Mozilla Firefox vulnerability
Last updated 25 August 2025
Other sources
Mozilla developers and community members Byron Campen, Jason Kratzer, and Christian Holler reported memory safety bugs present in Firefox 73 and Firefox ESR 68.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
— Mozilla
Mozilla developers and community members reported memory safety bugs present in Firefox 73 and Firefox ESR 68.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
External Reference:
https://www.mozilla.org/en-US/security/advisories/mfsa2020-09/#CVE-2020-6814
— Red Hat
Mozilla developers Byron Campen, Jason Kratzer, and Christian Holler reported memory safety bugs present in Firefox 73 and Firefox ESR 68.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
Mozilla developers Byron Campen, Jason Kratzer, and Christian Holler reported memory safety bugs present in Thunderbird 68.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
— Mozilla
Mozilla developers reported memory safety bugs present in Firefox and Thunderbird 68.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/firefoxto a version that resolves this vulnerability.Fixed in 68.6 - Upgrade
Upgrade
redhat/thunderbirdto a version that resolves this vulnerability.Fixed in 68.6 - Upgrade
Upgrade
Thunderbirdto a version that resolves this vulnerability.Fixed in 68.6 - Upgrade
Upgrade
Firefoxto a version that resolves this vulnerability.Fixed in 74 - Upgrade
Upgrade
Firefox ESRto a version that resolves this vulnerability.Fixed in 68.6 - Upgrade
Upgrade
debian/firefoxto a version that resolves this vulnerability.Fixed in 152.0.6-1 - Upgrade
Upgrade
debian/firefox-esrto a version that resolves this vulnerability.Fixed in 115.14.0esr-1~deb11u1Fixed in 140.13.0esr-1~deb11u1Fixed in 140.12.0esr-1~deb12u1Fixed in 140.13.0esr-1~deb12u1Fixed in 140.12.0esr-1~deb13u1Fixed in 140.13.0esr-1~deb13u1Fixed in 140.12.0esr-1Fixed in 140.13.0esr-2 - Upgrade
Upgrade
debian/thunderbirdto a version that resolves this vulnerability.Fixed in 1:115.12.0-1~deb11u1Fixed in 1:140.12.0esr-1~deb11u1Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:140.12.0esr-1 - Upgrade
Upgrade
Mozilla Firefoxto a version that resolves this vulnerability.Fixed in 74 - Upgrade
Upgrade
Mozilla Firefox ESRto a version that resolves this vulnerability.Fixed in 68.6 - Upgrade
Upgrade
Mozilla Thunderbirdto a version that resolves this vulnerability.Fixed in 68.6
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
What is CVE-2020-6814?
CVE-2020-6814 is a vulnerability reported in Mozilla Firefox 73 and Firefox ESR 68.5 that involves memory safety bugs with evidence of memory corruption.
How severe is CVE-2020-6814?
CVE-2020-6814 has a severity rating of high (7) based on the Common Vulnerability Scoring System (CVSS).
Which software versions are affected by CVE-2020-6814?
Mozilla Firefox versions up to exclusive 74, Mozilla Thunderbird versions up to exclusive 68.6, and Mozilla Firefox ESR versions up to exclusive 68.6 are affected by CVE-2020-6814.
How can CVE-2020-6814 be exploited?
CVE-2020-6814 could have been exploited with enough effort due to the memory corruption caused by the memory safety bugs.
Where can I find more information about CVE-2020-6814?
You can find more information about CVE-2020-6814 on the Mozilla Bugzilla and Mozilla Security Advisories websites.