CVE-2019-17022

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-01-08 · updated 2026-06-17
Weakness: CWE-79

Description

When pasting a <style> tag from the clipboard into a rich text editor, the CSS sanitizer does not escape < and > characters. Because the resulting string is pasted directly into the text node of the element this does not result in a direct injection into the webpage; however, if a webpage subsequently copies the node's innerHTML, assigning it to another innerHTML, this would result in an XSS vulnerability. Two WYSIWYG editors were identified with this behavior, more may exist. This vulnerability affects Firefox ESR < 68.4 and Firefox < 72.

Affected products

Canonical Ubuntu Linux: 16.04, 18.04, 19.04, 19.10
Debian Linux: 8.0, 9.0, 10.0
Mozilla Firefox: before 72.0 — fixed in 72.0
Mozilla Firefox ESR: before 68.4 — fixed in 68.4
RedHat Enterprise Linux Desktop: 6.0, 7.0
RedHat Enterprise Linux Server: 6.0, 7.0
RedHat Enterprise Linux Server Aus: 7.7
RedHat Enterprise Linux Server Tus: 7.7
RedHat Enterprise Linux Workstation: 6.0, 7.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 72.0; Mozilla Firefox ESR 68.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2019-17022 or the next vulnerability affects your stack