CVE-2019-11738 : Security Advisory and Response
Learn about CVE-2019-11738, a security vulnerability in Firefox and Firefox ESR versions prior to specific versions that allows the execution of harmful JavaScript content by bypassing Content Security Policy (CSP) permissions.
A security vulnerability in Firefox and Firefox ESR versions prior to specific versions allows the execution of harmful JavaScript content by bypassing Content Security Policy (CSP) permissions.
Understanding CVE-2019-11738
This CVE identifies a loophole in CSP directives that permits the execution of javascript: URIs, potentially leading to the running of malicious JavaScript content.
What is CVE-2019-11738?
If a CSP directive uses a hash-based source with an empty string as input, it allows the execution of javascript: URIs, enabling harmful JavaScript content to run and bypass CSP permissions.
The Impact of CVE-2019-11738
This vulnerability affects Firefox versions prior to 69 and Firefox ESR versions prior to 68.1, potentially exposing users to the execution of malicious JavaScript content.
Technical Details of CVE-2019-11738
This section provides detailed technical information about the vulnerability.
Vulnerability Description
The presence of a CSP directive using a hash-based source with an empty string as input allows the execution of javascript: URIs, bypassing CSP permissions.
Affected Systems and Versions
- Firefox versions prior to 69
- Firefox ESR versions prior to 68.1
Exploitation Mechanism
The vulnerability exploits a loophole in CSP directives, enabling the execution of javascript: URIs and potentially harmful JavaScript content.
Mitigation and Prevention
Protect your systems from CVE-2019-11738 with these mitigation strategies.
Immediate Steps to Take
- Update Firefox and Firefox ESR to versions 69 and 68.1 respectively.
- Disable javascript: URIs in the browser settings.
- Implement strict CSP policies to prevent unauthorized script execution.
Long-Term Security Practices
- Regularly update browsers and apply security patches promptly.
- Educate users on safe browsing practices and the importance of keeping software up to date.
Patching and Updates
- Stay informed about security advisories from Mozilla and promptly apply recommended patches to secure your systems.