CVE-2018-10546 Explained : Impact and Mitigation

A problem was found in earlier versions of PHP (before 5.6.36, 7.0.x before 7.0.30, 7.1.x before 7.1.17, and 7.2.x before 7.2.5) related to an endless loop in ext/iconv/iconv.c due to the iconv stream filter failing to reject invalid multibyte sequences.

Understanding CVE-2018-10546

What is CVE-2018-10546?

This CVE identifies an issue in PHP versions prior to 5.6.36, 7.0.x before 7.0.30, 7.1.x before 7.1.17, and 7.2.x before 7.2.5, involving an infinite loop in ext/iconv/iconv.c.

The Impact of CVE-2018-10546

The vulnerability allows for an endless loop to occur due to the failure to reject invalid multibyte sequences, potentially leading to denial of service or other security risks.

Technical Details of CVE-2018-10546

Vulnerability Description

An infinite loop exists in ext/iconv/iconv.c because the iconv stream filter does not reject invalid multibyte sequences.

Affected Systems and Versions

PHP versions before 5.6.36
PHP 7.0.x before 7.0.30
PHP 7.1.x before 7.1.17
PHP 7.2.x before 7.2.5

Exploitation Mechanism

The vulnerability can be exploited by crafting malicious input that triggers the endless loop in the iconv stream filter.

Mitigation and Prevention

Immediate Steps to Take

Update PHP to versions 5.6.36, 7.0.30, 7.1.17, or 7.2.5 or later to mitigate the vulnerability.
Monitor vendor advisories and apply patches promptly.

Long-Term Security Practices

Regularly update PHP and other software components to the latest secure versions.
Implement input validation and sanitization to prevent malicious input.

Patching and Updates

Apply patches provided by PHP and relevant vendors to address the vulnerability.