CVE-2023-50252 : Vulnerability Insights and Analysis

This article provides detailed information about CVE-2023-50252, a vulnerability in php-svg-lib that can lead to PHAR Deserialization vulnerability in PHP prior to version 8.

Understanding CVE-2023-50252

This CVE highlights an issue in php-svg-lib where unsafe attributes merge when parsing the

<use>

tag.

What is CVE-2023-50252?

php-svg-lib is an SVG file parsing/rendering library. Prior to version 0.5.1, a vulnerability exists when handling the

<use>

tag that references an

<image>

tag. It merges attributes from the

<use>

tag to the

<image>

tag, potentially leading to a PHAR Deserialization vulnerability.

The Impact of CVE-2023-50252

The vulnerability can result in an unsafe file read that triggers PHAR Deserialization vulnerability in PHP versions below 8. It poses a risk of external control of system/configuration settings.

Technical Details of CVE-2023-50252

This section delves into the specifics of the vulnerability.

Vulnerability Description

The issue arises when the

href

attribute from the

<use>

tag is not properly sanitized, allowing for unsafe attribute merging with the

<image>

tag, leading to potential file read vulnerabilities.

Affected Systems and Versions

Vendor dompdf's php-svg-lib versions prior to 0.5.1 are affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting malicious SVG files with specially designed

<use>

tags to trigger the unsafe attribute merging and potential PHAR Deserialization in vulnerable PHP versions.

Mitigation and Prevention

Protecting systems from CVE-2023-50252 requires immediate action and long-term security measures.

Immediate Steps to Take

Update to version 0.5.1 of php-svg-lib or later to apply the necessary patch and mitigate the vulnerability.
Ensure all input data, especially the

href

attribute, is properly sanitized to prevent exploitation.

Long-Term Security Practices

Regularly update software libraries and dependencies to stay protected against known vulnerabilities.
Implement secure coding practices to handle data inputs securely and mitigate risks of deserialization vulnerabilities.

Patching and Updates

Stay informed about security advisories and updates from dompdf to promptly apply patches and protect systems from potential exploits.