medium 6.5

CVE-2020-15652 json

By observing the stack trace for JavaScript errors in web workers, it was possible to leak the result of a cross-origin redirect.

published 2020-08-10 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-7639

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 69%
public exploits: 0; none known

By observing the stack trace for JavaScript errors in web workers, it was possible to leak the result of a cross-origin redirect. This applied only to content that can be parsed as script. This vulnerability affects Firefox < 79, Firefox ESR < 68.11, Firefox ESR < 78.1, Thunderbird < 68.11, and Thunderbird < 78.1.

Patch / fix

fixed in 3 distros 7

Mozilla Firefox 79
Mozilla Firefox ESR 68.11, 78.1
Mozilla Thunderbird 68.11, 78.1

debian ubuntu red hat suse opensuse alpine arch linux

firefox-esr Debian 14, Debian 13, Debian 12 68.11.0esr-1
thunderbird Debian 14, Debian 13, Debian 12 1:68.11.0-1

debian advisories DEBIAN-CVE-2020-15652

firefox Ubuntu 16.04 LTS 79.0+build1-0ubuntu0.16.04.2
firefox Ubuntu 18.04 LTS 79.0+build1-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 79.0+build1-0ubuntu0.20.04.1
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-2020-15652

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 68.11.0-1.el6_10
thunderbird RHEL 7 68.11.0-1.el7_8
thunderbird RHEL 8 68.11.0-1.el8_2
firefox RHEL 7 68.11.0-1.el7_8
firefox RHEL 8 68.11.0-1.el8_2
firefox RHEL 6 68.11.0-1.el6_10
thunderbird RHEL 8.1 EUS 68.11.0-1.el8_1
thunderbird RHEL 8.0 E4S 68.11.0-1.el8_0

red hat advisories RHSA-2020:3345 RHSA-2020:3344 RHSA-2020:3341 RHSA-2020:3342 RHSA-2020:3343 RHSA-2020:3254

MozillaThunderbird SLE Workstation Extension 15 SP2, SLE Workstation Extension 15 SP1 68.11.0-3.91.1
MozillaFirefox SLE Module for Desktop Applications 15 SP2 78.1.0-8.3.1
pipewire SLE Module for Desktop Applications 15 SP2 0.3.6-3.3.2
MozillaFirefox-branding-SLE SLE Module for Desktop Applications 15 SP2 78-9.2.4
MozillaFirefox SLE Module for Desktop Applications 15 SP1 78.1.0-3.100.2
MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +15 more 78.1.0-112.8.1
MozillaFirefox SLES 11 SP4-LTSS 78.1.0-78.87.1

suse advisories SUSE-SU-2020:14456-1 SUSE-SU-2020:2179-1 SUSE-SU-2020:2147-1 SUSE-SU-2020:2118-1 SUSE-SU-2020:2100-1

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 68.11.0-lp152.2.7.1
MozillaFirefox openSUSE Leap 15.2 78.1.0-lp152.2.15.1
pipewire openSUSE Leap 15.2 0.3.6-lp152.2.3.1
MozillaThunderbird openSUSE Leap 15.1 68.11.0-lp151.2.47.1
MozillaFirefox openSUSE Leap 15.2 78.1.0-lp152.2.12.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1 openSUSE-SU-2024:10601-1 openSUSE-SU-2020:1205-1 openSUSE-SU-2020:1189-1 openSUSE-SU-2020:1179-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 79.0-r0
mozjs68 Alpine 3.12 68.11.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 79.0-r0
firefox-esr Alpine 3.11 68.11.0-r0
firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 78.1.0-r0

alpine advisories ALPINE-CVE-2020-15652

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 79.0-1
thunderbird Arch Linux 68.12.0-1

arch linux advisories AVG-1213 AVG-1214

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-2020-15652 updated 2026-11-07 cvss 6.5

Mozilla: Potential leak of redirect targets when loading scripts in a worker

Red Hat Enterprise Linux 5 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 68.11.0-1.el8_2, thunderbird 68.11.0-1.el8_2
fixed: vendor fix RHSA-2020:3241
Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 68.11.0-1.el8_0, thunderbird 68.11.0-1.el8_0
fixed: vendor fix RHSA-2020:3229
Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox 68.11.0-1.el8_1, thunderbird 68.11.0-1.el8_1
fixed: vendor fix RHSA-2020:3254
Red Hat Enterprise Linux Client (v. 7) firefox 68.11.0-1.el7_8, thunderbird 68.11.0-1.el7_8 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.11.0-1.el7_8
fixed: vendor fix RHSA-2020:3253
Red Hat Enterprise Linux Desktop (v. 6) firefox 68.11.0-1.el6_10, thunderbird 68.11.0-1.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.11.0-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.11.0-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.11.0-1.el6_10
fixed: vendor fix RHSA-2020:3233
Red Hat Enterprise Linux Server (v. 7) firefox 68.11.0-1.el7_8
fixed: vendor fix RHSA-2020:3253
Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.11.0-1.el6_10, thunderbird 68.11.0-1.el6_10
fixed: vendor fix RHSA-2020:3233

show 5 more

Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.11.0-1.el7_8, thunderbird 68.11.0-1.el7_8
fixed: vendor fix RHSA-2020:3253
Red Hat Enterprise Linux Workstation (v. 6) firefox 68.11.0-1.el6_10, thunderbird 68.11.0-1.el6_10
fixed: vendor fix RHSA-2020:3233
Red Hat Enterprise Linux Workstation (v. 7) firefox 68.11.0-1.el7_8, thunderbird 68.11.0-1.el7_8
fixed: vendor fix RHSA-2020:3253
Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.11.0-1.el6_10
fixed: vendor fix RHSA-2020:3233
Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.11.0-1.el7_8
fixed: vendor fix RHSA-2020:3253

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

1.26% chance of exploitation in the next 30 days, higher than 69% 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:H/I:N/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

Mozilla Firefox
Mozilla Firefox ESR
Mozilla Thunderbird

Classification

Weakness

CWE-346 Origin Validation Error

References

lists.opensuse.org /opensuse-security-announce/2020-08/msg00022.html
vendor-advisory, third-party-advisory
lists.opensuse.org /opensuse-security-announce/2020-08/msg00025.html
vendor-advisory, third-party-advisory
lists.opensuse.org /opensuse-security-announce/2020-08/msg00032.html
vendor-advisory, broken-link
usn.ubuntu.com /4443-1/
vendor-advisory, third-party-advisory
mozilla.org /security/advisories/mfsa2020-30/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-35/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-32/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-33/
vendor-advisory
mozilla.org /security/advisories/mfsa2020-31/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1634872
issue-tracking, vendor-advisory

Sources

CVE List CVE-2020-15652
NVD CVE-2020-15652

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