What’s Vulnerable › Vulnerabilities

CVE-2020-6814

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-03-25 · updated 2026-06-17
• Weakness: CWE-787

Description

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.

Affected products

• Canonical Ubuntu Linux: 16.04, 18.04, 19.10
• Mozilla Firefox: before 74.0 — fixed in 74.0
• Mozilla Firefox ESR: before 68.6.0 — fixed in 68.6.0
• Mozilla Thunderbird: before 68.6.0 — fixed in 68.6.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 74.0; Mozilla Firefox ESR 68.6.0; Mozilla Thunderbird 68.6.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/buglist.cgi?bug_id=1592078%2C1604847%2C1608256%2C1612636%2C1614339
• https://usn.ubuntu.com/4328-1/
• https://usn.ubuntu.com/4335-1/
• https://www.mozilla.org/security/advisories/mfsa2020-08/
• https://www.mozilla.org/security/advisories/mfsa2020-09/
• https://www.mozilla.org/security/advisories/mfsa2020-10/
• https://bugzilla.mozilla.org/buglist.cgi?bug_id=1592078%2C1604847%2C1608256%2C1612636%2C1614339
• https://usn.ubuntu.com/4328-1/
• https://usn.ubuntu.com/4335-1/
• https://www.mozilla.org/security/advisories/mfsa2020-08/
• https://www.mozilla.org/security/advisories/mfsa2020-09/
• https://www.mozilla.org/security/advisories/mfsa2020-10/

Get alerted when CVE-2020-6814 or the next vulnerability affects your stack