What is CVE-2020-6801?

CVE-2020-6801 is a high-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2020-03-02.

How severe is CVE-2020-6801?

High severity. CVSS v3 base score is 8.8 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2020-6801

Mozilla developers reported memory safety bugs present in Firefox 72. 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 Firefox < 73.

Vulnerability class: Buffer Overflow

Published 2020-03-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (71.7th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 71.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Canonical Ubuntu Linux — versions 16.04

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

www.mozilla.org/security/advisories/mfsa2020-05/ (Vendor Advisory)
bugzilla.mozilla.org/buglist.cgi (Issue Tracking, Broken Link)
usn.ubuntu.com/4278-2/ (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2020-6801?: CVE-2020-6801 is a high-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2020-03-02.
How severe is CVE-2020-6801?: High severity. CVSS v3 base score is 8.8 out of 10.