CVE-2024-8927 is a vulnerability in the PHP interpreter affecting versions 8.1.*, 8.2.*, and 8.3.* prior to 8.1.30, 8.2.24, and 8.3.12 respectively. The issue stems from the way PHP uses the HTTP_REDIRECT_STATUS environment variable to determine if the CGI binary is being executed by the HTTP server. In certain configurations, this variable's content can be controlled by an attacker through crafted HTTP headers. This manipulation can cause the cgi.force_redirect directive, which is designed to prevent direct access to the PHP CGI binary, to be bypassed or not applied correctly. When this protection fails, it may allow an attacker to perform arbitrary file inclusion attacks. Such attacks can lead to disclosure of sensitive files or execution of malicious code if the included files contain executable PHP code. The vulnerability does not require any privileges or user interaction and can be exploited remotely over the network. Although no known exploits have been reported in the wild yet, the vulnerability is classified as high severity due to its potential impact on confidentiality and the ease of exploitation. The CWE-1220 classification indicates a weakness related to improper handling of environment variables leading to security bypass. This vulnerability primarily affects web servers running PHP in CGI mode with vulnerable versions, which is a common setup in many hosting environments.

For European organizations, the impact of CVE-2024-8927 can be significant, especially for those running web applications on vulnerable PHP versions in CGI mode. Successful exploitation could allow attackers to include arbitrary files, potentially exposing sensitive configuration files, source code, or other protected data, leading to confidentiality breaches. This could result in data leaks, intellectual property theft, or exposure of credentials. While the vulnerability does not directly affect integrity or availability, the information disclosure could facilitate further attacks such as privilege escalation or remote code execution if combined with other vulnerabilities. Organizations in sectors such as finance, healthcare, government, and e-commerce, which often rely on PHP-based web applications, may face increased risk. The ease of remote exploitation without authentication means attackers can target vulnerable servers at scale, increasing the threat landscape. Additionally, compliance with GDPR and other data protection regulations could be impacted if sensitive personal data is exposed due to this vulnerability.

1. Upgrade PHP to the fixed versions as soon as they are released: 8.1.30, 8.2.24, or 8.3.12 or later. 2. In the interim, review and harden the web server and PHP CGI configurations to ensure that cgi.force_redirect is enabled and properly enforced. 3. Implement strict input validation and sanitization on HTTP headers to reduce the risk of header manipulation. 4. Restrict direct access to the PHP CGI binary by configuring web server access controls and firewall rules. 5. Monitor web server logs for suspicious requests that attempt to manipulate HTTP_REDIRECT_STATUS or other environment variables. 6. Employ web application firewalls (WAFs) with rules designed to detect and block attempts to exploit this vulnerability. 7. Conduct regular vulnerability scanning and penetration testing focused on PHP CGI configurations. 8. Educate development and operations teams about secure PHP deployment practices, especially regarding CGI mode. 9. Isolate critical web applications and sensitive data to minimize exposure in case of exploitation. 10. Maintain an incident response plan to quickly address any exploitation attempts or breaches.