CVE intelligence and bounded remediation

CVE-2019-11741 — Mozilla Firefox security vulnerability

Medium CVSS 6.1

A compromised sandboxed content process can perform a Universal Cross-site Scripting (UXSS) attack on content from any site it can cause to be loaded in the same process. Because addons.mozilla.org and accounts.firefox.com have close ties to the Firefox product, malicious manipulation of these sites within the browser can potentially be used to modify a user's Firefox configuration. These two sites will now be isolated into their own process and not allowed to be loaded in a standard content process. This vulnerability affects Firefox < 69.

Severity
Medium
CVSS
6.1 (3.1)
Published
2019-09-27
CISA KEV
Not currently listed
Ecosystem
browser
Weaknesses
CWE-79

Affected products

  • mozilla / firefox

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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