high 8.8

CVE-2020-6811 json

The 'Copy as cURL' feature of Devtools' network tab did not properly escape the HTTP method of a request, which can be controlled by the we…

published 2020-03-25 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-27957

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 3.3%; EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits: 0; none known

The 'Copy as cURL' feature of Devtools' network tab did not properly escape the HTTP method of a request, which can be controlled by the website. If a user used the 'Copy as Curl' feature and pasted the command into a terminal, it could have resulted in command injection and arbitrary command execution. This vulnerability affects Thunderbird < 68.6, Firefox < 74, Firefox < ESR68.6, and Firefox ESR < 68.6.

Patch / fix

fixed in 3 distros 7

Mozilla Thunderbird 68.6
Mozilla Firefox 74, ESR68.6
Mozilla Firefox ESR 68.6

debian ubuntu red hat suse opensuse alpine arch linux

firefox-esr Debian 14, Debian 13, Debian 12 68.6.0esr-1
thunderbird Debian 14, Debian 13, Debian 12 1:68.6.0-1

debian advisories DEBIAN-CVE-2020-6811

firefox Ubuntu 16.04 LTS 74.0+build3-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 74.0+build3-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 74.0+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 1:68.6.0+build2-0ubuntu1

ubuntu advisories UBUNTU-CVE-2020-6811

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 8 68.6.0-1.el8_1
thunderbird RHEL 6 68.6.0-1.el6_10
thunderbird RHEL 7 68.6.0-1.el7_7
firefox RHEL 8 68.6.0-1.el8_1
firefox RHEL 7 68.6.0-1.el7_7
firefox RHEL 6 68.6.0-1.el6_10
thunderbird RHEL 8.0 E4S 68.6.0-1.el8_0
firefox RHEL 8.0 E4S 68.6.0-1.el8_0

red hat advisories RHSA-2020:0919 RHSA-2020:0914 RHSA-2020:0918 RHSA-2020:0905 RHSA-2020:0820 RHSA-2020:0819

MozillaThunderbird SLE Workstation Extension 15 SP1 68.6.0-3.74.1
MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +16 more 68.6.0-109.110.1
MozillaFirefox SLE Module for Desktop Applications 15 SP1 68.6.0-3.75.1
MozillaFirefox SLES 11 SP4-LTSS 68.6.0-78.64.1

suse advisories SUSE-SU-2020:0721-1 SUSE-SU-2020:0717-1 SUSE-SU-2020:0686-1 SUSE-SU-2020:14312-1

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 68.6.0-lp151.2.28.1
MozillaFirefox openSUSE Leap 15.1 68.6.0-lp151.2.33.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2020:0366-1 openSUSE-SU-2020:0340-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 74.0-r0
mozjs68 Alpine 3.12 68.6.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 74.0-r0
firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +10 more 68.6.0-r0
thunderbird Alpine 3.23, Alpine 3.22, Alpine 3.21 +5 more 68.6.0-r0

alpine advisories ALPINE-CVE-2020-6811

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 74.0-1
thunderbird Arch Linux 68.6.0-1

arch linux advisories AVG-1112 AVG-1115

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-2020-6811 updated 2026-11-05 cvss 8.8

Mozilla: Devtools' 'Copy as cURL' feature did not fully escape website-controlled data, potentially leading to command injection

Red Hat Enterprise Linux 5 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 68.6.0-1.el8_1, thunderbird 68.6.0-1.el8_1
fixed: vendor fix RHSA-2020:0820
Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 68.6.0-1.el8_0, thunderbird 68.6.0-1.el8_0
fixed: vendor fix RHSA-2020:0819
Red Hat Enterprise Linux Client (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.6.0-1.el7_7
fixed: vendor fix RHSA-2020:0815
Red Hat Enterprise Linux Desktop (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.6.0-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.6.0-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.6.0-1.el6_10
fixed: vendor fix RHSA-2020:0816
Red Hat Enterprise Linux Server (v. 7) firefox 68.6.0-1.el7_7
fixed: vendor fix RHSA-2020:0815
Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10
fixed: vendor fix RHSA-2020:0816
Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7
fixed: vendor fix RHSA-2020:0815

show 4 more

Red Hat Enterprise Linux Workstation (v. 6) firefox 68.6.0-1.el6_10, thunderbird 68.6.0-1.el6_10
fixed: vendor fix RHSA-2020:0816
Red Hat Enterprise Linux Workstation (v. 7) firefox 68.6.0-1.el7_7, thunderbird 68.6.0-1.el7_7
fixed: vendor fix RHSA-2020:0815
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.6.0-1.el6_10
fixed: vendor fix RHSA-2020:0816
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.6.0-1.el7_7
fixed: vendor fix RHSA-2020:0815

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

3.27% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1607742 referenced PoC, tagged "exploit" by a source, unverified

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
Mozilla Firefox ESR

Classification

Weakness

CWE-77 Improper Neutralization of Special Elements used in a Command

References

bugzilla.mozilla.org /show_bug.cgi?id=1607742
exploit, issue-tracking, vendor-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/mfsa2020-08/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-10/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-09/
vendor-advisory

Sources

CVE List CVE-2020-6811
NVD CVE-2020-6811

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