CVE-2019-11040 : What You Need to Know

In versions of PHP below 7.1.30, 7.2.19, and 7.3.6, a vulnerability exists in the PHP EXIF extension that could lead to information disclosure or system crashes.

Understanding CVE-2019-11040

This CVE involves a heap buffer overflow in the PHP EXIF extension, affecting versions 7.1.30, 7.2.19, and 7.3.6.

What is CVE-2019-11040?

When the PHP EXIF extension parses EXIF information from an image using the exif_read_data() function, supplying it with excessive data can cause it to read beyond the allocated buffer, potentially resulting in information exposure or system instability.

The Impact of CVE-2019-11040

The vulnerability has a CVSS base score of 4.8, indicating a medium severity issue with a high attack complexity and network-based attack vector. While the confidentiality impact is low, it could lead to information disclosure or system crashes.

Technical Details of CVE-2019-11040

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability arises when the PHP EXIF extension processes EXIF data from an image, allowing attackers to exceed the allocated buffer size, potentially leading to security breaches or system failures.

Affected Systems and Versions

Affected versions: PHP 7.1.30, 7.2.19, 7.3.6

Exploitation Mechanism

Attackers can exploit this vulnerability by providing the exif_read_data() function with data that surpasses the allocated buffer, triggering the overflow.

Mitigation and Prevention

To address CVE-2019-11040, immediate actions and long-term security practices are crucial.

Immediate Steps to Take

Update PHP to versions 7.1.30, 7.2.19, or 7.3.6 to mitigate the vulnerability.
Monitor official security advisories for patches and updates.

Long-Term Security Practices

Regularly update PHP and its extensions to the latest secure versions.
Implement secure coding practices to prevent buffer overflows and other vulnerabilities.

Patching and Updates

Apply patches provided by PHP Group or relevant vendors to fix the heap buffer overflow issue.