CVE intelligence and bounded remediation

CVE-2019-17022 — When pasting a <style> tag from the clipboard into a rich text editor, the CSS sanitizer does not escape < and > characters

Medium CVSS 6.1

When pasting a &lt;style&gt; tag from the clipboard into a rich text editor, the CSS sanitizer does not escape &lt; and &gt; 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.

Severity
Medium
CVSS
6.1 (3.1)
Published
2020-01-08
CISA KEV
Not currently listed
Ecosystem
browser
Weaknesses
CWE-79

Affected products

  • mozilla / firefox
  • mozilla / firefox_esr
  • canonical / ubuntu_linux / 16.04
  • canonical / ubuntu_linux / 18.04
  • canonical / ubuntu_linux / 19.04
  • canonical / ubuntu_linux / 19.10

Showing 6 representative product identities from 17 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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