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Fencer Vulns
medium 6.1

CVE-2019-17016 json

When pasting a <style> tag from the clipboard into a rich text editor, the CSS sanitizer incorrectly rewrites a @namespace rule.

published 2020-01-08 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-7490

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer incorrectly rewrites a @namespace rule. This could allow for injection into certain types of websites resulting in data exfiltration. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

Patch / fix

  • mozilla firefox 72.0
  • mozilla firefox_esr 68.4
  • firefox-esr Debian 14, Debian 13, Debian 12 68.4.0esr-1
  • thunderbird Debian 14, Debian 13, Debian 12 1:68.4.1-1

debian advisories DEBIAN-CVE-2019-17016

  • firefox Ubuntu 16.04 LTS 72.0.1+build1-0ubuntu0.16.04.1
  • firefox Ubuntu 18.04 LTS 72.0.1+build1-0ubuntu0.18.04.1
  • firefox Ubuntu 20.04 LTS 72.0.1+build1-0ubuntu1
  • thunderbird Ubuntu 16.04 LTS 1:68.7.0+build1-0ubuntu0.16.04.2
  • thunderbird Ubuntu 18.04 LTS 1:68.4.1+build1-0ubuntu0.18.04.1
  • thunderbird Ubuntu 20.04 LTS 1:68.4.1+build1-0ubuntu1

ubuntu advisories UBUNTU-CVE-2019-17016

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 68.4.1-2.el6_10
  • thunderbird RHEL 7 68.4.1-2.el7_7
  • thunderbird RHEL 8 68.4.1-2.el8_1
  • firefox RHEL 8 68.4.1-1.el8_1
  • firefox RHEL 6 68.4.1-1.el6_10
  • firefox RHEL 7 68.4.1-1.el7_7
  • firefox RHEL 8.0 E4S 68.4.1-1.el8_0
  • thunderbird RHEL 8.0 E4S 68.4.1-2.el8_0

red hat advisories RHSA-2020:0295RHSA-2020:0292RHSA-2020:0123RHSA-2020:0120RHSA-2020:0127RHSA-2020:0111

  • MozillaThunderbird SLE Workstation Extension 15 SP1, SLE Workstation Extension 15 68.4.1-3.66.1
  • MozillaFirefox SLE Module for Desktop Applications 15 SP1, SLE Module for Desktop Applications 15 68.4.1-3.66.1
  • MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +17 more 68.4.1-109.101.1
  • MozillaFirefox SLES 11 SP4-LTSS 68.4.1-78.57.1

suse advisories SUSE-SU-2020:0142-1SUSE-SU-2020:0078-1SUSE-SU-2020:14268-1SUSE-SU-2020:0068-1

  • 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 68.4.1-lp151.2.22.2
  • MozillaFirefox openSUSE Leap 15.1 68.4.1-lp151.2.24.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2024:10601-1openSUSE-SU-2020:0094-1openSUSE-SU-2020:0060-1

  • firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 71.0.1-r0
  • librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 71.0.1-r0
  • firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +10 more 68.4.1-r0

alpine advisories ALPINE-CVE-2019-17016

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 72.0-1
  • thunderbird Arch Linux 68.4.1-1

arch linux advisories AVG-1084AVG-1086

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-2019-17016 updated cvss 6.1

Mozilla: Bypass of @namespace CSS sanitization during pasting

  • Red Hat Enterprise Linux 5 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 68.4.1-1.el8_1, thunderbird 68.4.1-2.el8_1
    fixed: vendor fix RHSA-2020:0111
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox 68.4.1-1.el8_0, thunderbird 68.4.1-2.el8_0
    fixed: vendor fix RHSA-2020:0295
  • Red Hat Enterprise Linux Client (v. 7) firefox 68.4.1-1.el7_7, thunderbird 68.4.1-2.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) firefox 68.4.1-1.el7_7
    fixed: vendor fix RHSA-2020:0085
  • Red Hat Enterprise Linux Desktop (v. 6) firefox 68.4.1-1.el6_10, thunderbird 68.4.1-2.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 68.4.1-1.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 68.4.1-1.el6_10 Red Hat Enterprise Linux Server (v. 6) firefox 68.4.1-1.el6_10
    fixed: vendor fix RHSA-2020:0086
  • Red Hat Enterprise Linux Server (v. 7) firefox 68.4.1-1.el7_7
    fixed: vendor fix RHSA-2020:0085
  • Red Hat Enterprise Linux Server Optional (v. 6) firefox 68.4.1-1.el6_10, thunderbird 68.4.1-2.el6_10
    fixed: vendor fix RHSA-2020:0086
  • Red Hat Enterprise Linux Server Optional (v. 7) firefox 68.4.1-1.el7_7, thunderbird 68.4.1-2.el7_7
    fixed: vendor fix RHSA-2020:0085
show 4 more
  • Red Hat Enterprise Linux Workstation (v. 6) firefox 68.4.1-1.el6_10, thunderbird 68.4.1-2.el6_10
    fixed: vendor fix RHSA-2020:0086
  • Red Hat Enterprise Linux Workstation (v. 7) firefox 68.4.1-1.el7_7, thunderbird 68.4.1-2.el7_7
    fixed: vendor fix RHSA-2020:0085
  • Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 68.4.1-1.el6_10
    fixed: vendor fix RHSA-2020:0086
  • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 68.4.1-1.el7_7
    fixed: vendor fix RHSA-2020:0085

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

1.99% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

  • Mozilla Firefox ESR
  • Mozilla Firefox

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

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.