Out-of-Bounds Write Vulnerability in PHP Affects Multiple Versions

CVE-2026-17544

What is CVE-2026-17544?

CVE-2026-17544 is an out-of-bounds write vulnerability found in multiple versions of the PHP programming language, specifically affecting PHP versions prior to 8.4.24 and 8.5.9. PHP is widely used for web development and server-side scripting, powering a significant portion of websites and applications globally. This vulnerability arises from improper handling of attacker-supplied input within the bccomp() function, which is designed for arbitrary precision mathematics. When exploited, it can lead to corruption of both stack and heap memory, allowing attackers to potentially manipulate the execution flow of the application. Given the extensive use of PHP in web-based applications, this vulnerability presents a serious threat to the stability and security of affected systems, potentially leading to unauthorized access, data integrity issues, and broader system compromise.

Potential impact of CVE-2026-17544

1. Remote Code Execution: The out-of-bounds write could enable an attacker to execute arbitrary code on the affected server, which can lead to full system control and the ability to install malware or access sensitive information.

2. Data Corruption: Due to the nature of stack and heap corruption, there is a heightened risk of data integrity issues, where attackers can alter or destroy critical data, leading to data loss and potential business disruptions.

3. Service Availability: Exploitation of this vulnerability could result in crashes or denial of service, affecting the availability of web applications running on vulnerable PHP versions, and leading to considerable downtime and loss of trust from users.

References