medium 6.5

CVE-2020-15664 json

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigge…

published 2020-10-01 6 y ago modified 2026-08-19 2 mo ago also EUVD-2020-7651

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits: 0; none known

By holding a reference to the eval() function from an about:blank window, a malicious webpage could have gained access to the InstallTrigger object which would allow them to prompt the user to install an extension. Combined with user confusion, this could result in an unintended or malicious extension being installed. This vulnerability affects Firefox < 80, Thunderbird < 78.2, Thunderbird < 68.12, Firefox ESR < 68.12, Firefox ESR < 78.2, and Firefox for Android < 80.

Patch / fix

fixed in 4 distros 6

Mozilla Firefox 80
Mozilla Thunderbird 68.12, 78.2
Mozilla Firefox ESR 68.12, 78.2
Mozilla Firefox for Android 80

debian ubuntu red hat suse opensuse alpine

firefox-esr Debian 14, Debian 13, Debian 12 68.12.0esr-1
thunderbird Debian 14, Debian 13, Debian 12 1:68.12.0-1

debian advisories DEBIAN-CVE-2020-15664

firefox Ubuntu 16.04 LTS 80.0+build2-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 80.0+build2-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 80.0+build2-0ubuntu0.20.04.1
thunderbird Ubuntu 18.04 LTS 1:78.8.1+build1-0ubuntu0.18.04.1
thunderbird Ubuntu 20.04 LTS 1:78.7.1+build1-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-15664

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 6 68.12.0-1.el6_10
thunderbird RHEL 8 68.12.0-1.el8_2
thunderbird RHEL 7 68.12.0-1.el7_8
firefox RHEL 6 68.12.0-1.el6_10
firefox RHEL 7 68.12.0-1.el7_8
firefox RHEL 8 78.2.0-2.el8_2
thunderbird RHEL 8.0 E4S 68.12.0-1.el8_0
thunderbird RHEL 8.1 EUS 68.12.0-1.el8_1

red hat advisories RHSA-2020:3643 RHSA-2020:3634 RHSA-2020:3633 RHSA-2020:3632 RHSA-2020:3631 RHSA-2020:3558

MozillaFirefox SLE Module for Desktop Applications 15 SP2 78.3.0-8.6.1
MozillaFirefox SLE Module for Desktop Applications 15 SP1 78.2.0-3.105.1
MozillaThunderbird SLE Workstation Extension 15 SP2, SLE Workstation Extension 15 SP1 68.12.0-3.94.1
MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +15 more 78.2.0-112.19.2
MozillaFirefox SLES 11 SP4-LTSS 78.2.0-78.90.2

suse advisories SUSE-SU-2020:2749-1 SUSE-SU-2020:14489-1 SUSE-SU-2020:2563-1 SUSE-SU-2020:2552-1 SUSE-SU-2020:2544-1

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 15.2 68.12.0-lp152.2.10.1
MozillaFirefox openSUSE Leap 15.2 78.2.0-lp152.2.18.1
MozillaFirefox openSUSE Leap 15.1 78.2.0-lp151.2.65.1
MozillaThunderbird openSUSE Leap 15.1 68.12.0-lp151.2.50.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2020:1392-1 openSUSE-SU-2020:1391-1 openSUSE-SU-2020:1384-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 80.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 80.0-r0
firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 78.2.0-r0

alpine advisories ALPINE-CVE-2020-15664

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

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-2020-15664 updated 2026-11-07 cvss 6.5

Mozilla: Attacker-induced prompt for extension installation

Red Hat Enterprise Linux 5 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 78.2.0-2.el8_2, thunderbird 68.12.0-1.el8_2
fixed: vendor fix RHSA-2020:3557
Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 78.2.0-3.el8_0, thunderbird 68.12.0-1.el8_0
fixed: vendor fix RHSA-2020:3555
Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox 78.2.0-3.el8_1, thunderbird 68.12.0-1.el8_1
fixed: vendor fix RHSA-2020:3559
Red Hat Enterprise Linux Client (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.12.0-1.el7_8
fixed: vendor fix RHSA-2020:3556
Red Hat Enterprise Linux Desktop (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.12.0-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.12.0-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.12.0-1.el6_10
fixed: vendor fix RHSA-2020:3558
Red Hat Enterprise Linux Server (v. 7) firefox 68.12.0-1.el7_8
fixed: vendor fix RHSA-2020:3556
Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10
fixed: vendor fix RHSA-2020:3558

show 5 more

Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8
fixed: vendor fix RHSA-2020:3556
Red Hat Enterprise Linux Workstation (v. 6) firefox 68.12.0-1.el6_10, thunderbird 68.12.0-1.el6_10
fixed: vendor fix RHSA-2020:3558
Red Hat Enterprise Linux Workstation (v. 7) firefox 68.12.0-1.el7_8, thunderbird 68.12.0-1.el7_8
fixed: vendor fix RHSA-2020:3556
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.12.0-1.el6_10
fixed: vendor fix RHSA-2020:3558
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.12.0-1.el7_8
fixed: vendor fix RHSA-2020:3556

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

1.39% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

Mozilla Firefox
Mozilla Thunderbird
Mozilla Firefox ESR
Mozilla Firefox for Android

Classification

Weakness

CWE-863 Incorrect Authorization

References

mozilla.org /security/advisories/mfsa2020-39/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-41/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-36/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-38/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-40/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-37/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1658214
issue-tracking, permissions-required, vendor-advisory

Sources

CVE List CVE-2020-15664
NVD CVE-2020-15664

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