CVE-2019-17020 : What You Need to Know
Learn about CVE-2019-17020, a Firefox vulnerability allowing XSL stylesheets with JavaScript to evade Content Security Policy restrictions. Find mitigation steps and preventive measures here.
A vulnerability in Firefox versions prior to 72 allows XSL stylesheets containing JavaScript to bypass Content Security Policy restrictions.
Understanding CVE-2019-17020
This CVE involves a security issue in Firefox that enables XSL stylesheets with JavaScript to evade Content Security Policy restrictions.
What is CVE-2019-17020?
When an XML file includes an XSL stylesheet with JavaScript, the Content Security Policy fails to apply restrictions to the XSL stylesheet, allowing it to bypass security limitations on the XML document.
The Impact of CVE-2019-17020
This vulnerability in Firefox versions before 72 poses a risk of bypassing Content Security Policy restrictions, potentially leading to unauthorized access or malicious activities.
Technical Details of CVE-2019-17020
The technical aspects of this CVE provide insight into the vulnerability's description, affected systems, and exploitation mechanism.
Vulnerability Description
The vulnerability allows XSL stylesheets with JavaScript to circumvent Content Security Policy restrictions, potentially compromising the security of XML documents.
Affected Systems and Versions
- Product: Firefox
- Vendor: Mozilla
- Versions Affected: Before 72
Exploitation Mechanism
By including JavaScript in XSL stylesheets within XML files, attackers can exploit this vulnerability to bypass Content Security Policy restrictions.
Mitigation and Prevention
Protecting systems from CVE-2019-17020 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Update Firefox to version 72 or later to mitigate the vulnerability.
- Avoid opening untrusted XML files with XSL stylesheets containing JavaScript.
Long-Term Security Practices
- Regularly update browsers and security software to prevent known vulnerabilities.
- Implement strict Content Security Policies to restrict potentially harmful scripts.
Patching and Updates
Ensure timely installation of security patches and updates to address vulnerabilities like CVE-2019-17020.