CVE-2019-11711 Explained : Impact and Mitigation

A vulnerability in Firefox ESR, Firefox, and Thunderbird could allow script injection within domains through inner window reuse.

Understanding CVE-2019-11711

This CVE identifies a security flaw in Mozilla products that could be exploited for script injection across subdomains.

What is CVE-2019-11711?

When reusing an inner window, the vulnerability fails to consider document.domain for cross-origin protections. This oversight enables pages on different subdomains to inject scripts into each other, even without relaxing origin security.

The Impact of CVE-2019-11711

The vulnerability affects Firefox ESR < 60.8, Firefox < 68, and Thunderbird < 60.8, potentially allowing malicious script injections across subdomains.

Technical Details of CVE-2019-11711

This section delves into the specifics of the vulnerability.

Vulnerability Description

The flaw arises from the improper handling of document.domain during inner window reuse, enabling cross-subdomain script injections.

Affected Systems and Versions

Firefox ESR < 60.8
Firefox < 68
Thunderbird < 60.8

Exploitation Mechanism

By exploiting the lack of consideration for document.domain, attackers can inject scripts across subdomains, compromising security.

Mitigation and Prevention

Protecting systems from CVE-2019-11711 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update affected products to versions above the specified vulnerable ones.
Monitor for any suspicious activities indicating script injections.

Long-Term Security Practices

Implement strict cross-origin policies to prevent unauthorized script injections.
Regularly update software to patch known vulnerabilities.

Patching and Updates

Apply security patches provided by Mozilla to address the vulnerability and prevent potential script injections.