CVE-2018-7753 : Security Advisory and Response

A vulnerability was found in Bleach 2.1.x versions prior to 2.1.3, allowing unauthorized schemes to bypass the sanitization process.

Understanding CVE-2018-7753

What is CVE-2018-7753?

This CVE identifies an issue in Bleach versions where attributes containing URIs with character entities were not properly sanitized, enabling the creation of URIs with unauthorized schemes.

The Impact of CVE-2018-7753

Exploiting this vulnerability could lead to security bypasses and potentially malicious URI values being accepted without proper sanitization.

Technical Details of CVE-2018-7753

Vulnerability Description

The flaw in Bleach 2.1.x versions allowed the construction of URIs with unauthorized schemes due to improper sanitization of attributes with URIs containing character entities.

Affected Systems and Versions

Product: Bleach
Vendor: N/A
Versions affected: 2.1.x (prior to 2.1.3)

Exploitation Mechanism

By utilizing character entities in attribute values, attackers could create URIs with unauthorized schemes, bypassing the sanitization process.

Mitigation and Prevention

Immediate Steps to Take

Update Bleach to version 2.1.3 or later to mitigate the vulnerability.
Regularly sanitize and validate input data to prevent similar issues.

Long-Term Security Practices

Implement input validation mechanisms to ensure data integrity.
Conduct security audits and code reviews to identify and address vulnerabilities.

Patching and Updates

Apply patches and updates provided by Bleach promptly to address security vulnerabilities.