high 8.8

CVE-2020-6800 json

Mozilla developers and community members reported memory safety bugs present in Firefox 72 and Firefox ESR 68.4.

published 2020-03-02 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-27947

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.3%; EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits: 0; none known

Mozilla developers and community members reported memory safety bugs present in Firefox 72 and Firefox ESR 68.4. 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. In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or browser-like contexts. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.

Patch / fix

fixed in 2 distros 7

Mozilla Thunderbird 68.5
Mozilla Firefox 73, ESR68.5

debian ubuntu red hat suse opensuse alpine arch linux

firefox-esr Debian 14, Debian 13, Debian 12 68.5.0esr-1
thunderbird Debian 14, Debian 13, Debian 12 1:68.5.0-1

debian advisories DEBIAN-CVE-2020-6800

firefox Ubuntu 16.04 LTS 73.0.1+build1-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 73.0+build3-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 73.0+build3-0ubuntu1
thunderbird Ubuntu 16.04 LTS 1:68.7.0+build1-0ubuntu0.16.04.2
thunderbird Ubuntu 18.04 LTS 1:68.7.0+build1-0ubuntu0.18.04.1
thunderbird Ubuntu 20.04 LTS 1:68.5.0+build1-0ubuntu1

ubuntu advisories UBUNTU-CVE-2020-6800

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

thunderbird RHEL 7 68.5.0-1.el7_7
thunderbird RHEL 6 68.5.0-1.el6_10
thunderbird RHEL 8 68.5.0-1.el8_1
firefox RHEL 6 68.5.0-2.el6_10
firefox RHEL 7 68.5.0-2.el7_7
firefox RHEL 8 68.5.0-2.el8_1
thunderbird RHEL 8.0 E4S 68.5.0-1.el8_0
firefox RHEL 8.0 E4S 68.5.0-2.el8_0

red hat advisories RHSA-2020:0576 RHSA-2020:0574 RHSA-2020:0577 RHSA-2020:0565 RHSA-2020:0519 RHSA-2020:0521

MozillaThunderbird SLE Workstation Extension 15 SP1 68.5.0-3.71.1
MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +17 more 68.5.0-109.106.1
MozillaFirefox SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 68.5.0-3.72.1
MozillaFirefox SLES 11 SP4-LTSS 68.5.0-78.61.2

suse advisories SUSE-SU-2020:14290-1 SUSE-SU-2020:0385-1 SUSE-SU-2020:0384-1 SUSE-SU-2020:0383-1

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 92.0-1.2
MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
MozillaThunderbird openSUSE Leap 15.1 68.5.0-lp151.2.25.1
MozillaFirefox openSUSE Leap 15.1 68.5.0-lp151.2.30.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2020:0231-1 openSUSE-SU-2020:0230-1

firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +10 more 68.5.0-r0
thunderbird Alpine 3.23, Alpine 3.22, Alpine 3.21 +5 more 68.5.0-r0

alpine advisories ALPINE-CVE-2020-6800

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

firefox Arch Linux 73.0-1
thunderbird Arch Linux 68.5.0-1

arch linux advisories AVG-1096 AVG-1099

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-6800 updated 2026-11-04 cvss 8.8

Mozilla: Memory safety bugs fixed in Firefox 73 and Firefox ESR 68.5

Red Hat Enterprise Linux 5 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 68.5.0-2.el8_1, thunderbird 68.5.0-1.el8_1
fixed: vendor fix RHSA-2020:0512
Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 68.5.0-2.el8_0, thunderbird 68.5.0-1.el8_0
fixed: vendor fix RHSA-2020:0519
Red Hat Enterprise Linux Client (v. 7) firefox 68.5.0-2.el7_7, thunderbird 68.5.0-1.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.5.0-2.el7_7
fixed: vendor fix RHSA-2020:0520
Red Hat Enterprise Linux Desktop (v. 6) firefox 68.5.0-2.el6_10, thunderbird 68.5.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.5.0-2.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.5.0-2.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.5.0-2.el6_10
fixed: vendor fix RHSA-2020:0521
Red Hat Enterprise Linux Server (v. 7) firefox 68.5.0-2.el7_7
fixed: vendor fix RHSA-2020:0520
Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.5.0-2.el6_10, thunderbird 68.5.0-1.el6_10
fixed: vendor fix RHSA-2020:0521
Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.5.0-2.el7_7, thunderbird 68.5.0-1.el7_7
fixed: vendor fix RHSA-2020:0520

show 4 more

Red Hat Enterprise Linux Workstation (v. 6) firefox 68.5.0-2.el6_10, thunderbird 68.5.0-1.el6_10
fixed: vendor fix RHSA-2020:0521
Red Hat Enterprise Linux Workstation (v. 7) firefox 68.5.0-2.el7_7, thunderbird 68.5.0-1.el7_7
fixed: vendor fix RHSA-2020:0520
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.5.0-2.el6_10
fixed: vendor fix RHSA-2020:0521
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.5.0-2.el7_7
fixed: vendor fix RHSA-2020:0520

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.26% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	2.0	6.8	AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

Mozilla Thunderbird
Mozilla Firefox

Classification

Weakness

CWE-787 Out-of-bounds Write

References

usn.ubuntu.com /4278-2/
vendor-advisory, third-party-advisory
security.gentoo.org /glsa/202003-02
vendor-advisory, third-party-advisory
security.gentoo.org /glsa/202003-10
vendor-advisory, third-party-advisory
usn.ubuntu.com /4328-1/
vendor-advisory, third-party-advisory
usn.ubuntu.com /4335-1/
vendor-advisory, third-party-advisory
mozilla.org /security/advisories/mfsa2020-05/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-06/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-07/
vendor-advisory
bugzilla.mozilla.org /buglist.cgi?bug_id=1595786%2C1596706%2C1598543%2C1604851%2C1608580%2C1608785%2C1605777
broken-link, issue-tracking

Sources

CVE List CVE-2020-6800
NVD CVE-2020-6800

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary