CVE-2020-8923 : Security Advisory and Response

An improper HTML sanitization in Dart versions up to and including 2.7.1 and dev versions 2.8.0-dev.16.0 allows an attacker to inject custom HTML/JavaScript (XSS) using DOM Clobbering techniques. Update to Dart SDK 2.7.2 or 2.8.0-dev.17.0 to mitigate this vulnerability.

Understanding CVE-2020-8923

This CVE identifies an XSS vulnerability in Dart SDK versions.

What is CVE-2020-8923?

CVE-2020-8923 is an XSS vulnerability in Dart SDK versions up to 2.7.1 and 2.8.0-dev.16.0, enabling attackers to bypass HTML sanitization.

The Impact of CVE-2020-8923

CVSS Base Score: 5.4 (Medium Severity)
Attack Vector: Network
Attack Complexity: Low
User Interaction: Required
Confidentiality Impact: Low
Integrity Impact: Low
Privileges Required: None
Scope: Unchanged
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Technical Details of CVE-2020-8923

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability allows attackers to perform XSS attacks by leveraging DOM Clobbering techniques in affected Dart SDK versions.

Affected Systems and Versions

Affected Product: Dart SDK
Vendor: Google
Affected Versions:
Dart SDK 2.7.1 (stable)
Dart SDK 2.8.0-dev.16.0 (dev)

Exploitation Mechanism

Attackers exploit the vulnerability by injecting custom HTML/JavaScript using DOM Clobbering techniques.

Mitigation and Prevention

Protect your systems from CVE-2020-8923 with the following steps:

Immediate Steps to Take

Update Dart SDK to version 2.7.2 (stable) or 2.8.0-dev.17.0 (dev)
Review API usage for affected APIs
Use Element.innerText or Node.text for populating DOM elements

Long-Term Security Practices

Regularly update software and libraries
Implement input validation and output encoding
Conduct security training for developers

Patching and Updates

Apply patches and updates provided by Google for Dart SDK