CVE-2021-43991 Explained : Impact and Mitigation

Kentico Xperience CMS version 13.0 – 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability. Attackers can exploit this to execute malicious scripts, potentially leading to a range of attacks.

Understanding CVE-2021-43991

Kentico Xperience CMS version 13.0 – 13.0.43 suffers from a persistent XSS vulnerability that can have severe consequences for affected users.

What is CVE-2021-43991?

Persistent XSS in Kentico Xperience CMS allows attackers to store and execute malicious scripts through user-supplied data.
Exploitation of this vulnerability can result in session hijacking, account takeovers, and unauthorized access to sensitive information.

The Impact of CVE-2021-43991

Base Score: 6.8 (Medium Severity)
Attack Vector: Network
Confidentiality Impact: High
User Interaction: Required
Vulnerability Type: Cross-site Scripting (XSS) - CWE-79
The application fails to handle dangerous content properly, enabling attackers to execute malicious scripts on other users' devices.

Technical Details of CVE-2021-43991

Kentico Xperience CMS version 13.0 – 13.0.43 is susceptible to a persistent XSS vulnerability due to inadequate data handling.

Vulnerability Description

The vulnerability stems from improper storage and retrieval of client-supplied data without content validation.
Attackers can inject malicious scripts, leading to various security risks for application users.

Affected Systems and Versions

Product: Kentico Xperience XMS
Vendor: Kentico
Versions Affected: 13.0 (custom)

Exploitation Mechanism

Attack Complexity: Low
Privileges Required: Low
Scope: Changed
Successful exploitation necessitates user interaction and can be achieved through network access.

Mitigation and Prevention

To address CVE-2021-43991, immediate actions and long-term security practices are crucial.

Immediate Steps to Take

Patch the Kentico Xperience CMS to version 13.0.44 or higher.
Implement proper input validation and output encoding to mitigate XSS risks.
Regularly monitor and audit user-generated content for potential threats.

Long-Term Security Practices

Educate developers and users on secure coding practices and awareness of XSS vulnerabilities.
Conduct regular security assessments and penetration testing to identify and address vulnerabilities proactively.

Patching and Updates

Stay informed about security patches and updates from Kentico to ensure the CMS is protected against known vulnerabilities.