CVE-2025-65082 is a vulnerability classified under CWE-150, which pertains to improper neutralization of escape, meta, or control sequences. Specifically, this issue arises in Apache HTTP Server versions 2.4.0 through 2.4.65, where environment variables set via the Apache configuration can unexpectedly supersede variables that the server calculates internally for CGI (Common Gateway Interface) programs. CGI programs rely on environment variables to receive input and context from the web server; if these variables are manipulated or overridden improperly, it can lead to unintended behavior such as information leakage or manipulation of CGI execution flow. The vulnerability stems from insufficient sanitization or validation of these environment variables, allowing crafted configuration directives to inject escape or control sequences that alter the expected server-to-CGI communication. Exploitation requires no authentication or user interaction and can be performed remotely by an attacker who can influence the server configuration or deploy malicious configurations. The CVSS v3.1 base score is 6.5 (medium), reflecting network attack vector, low complexity, no privileges required, no user interaction, and partial impact on confidentiality and integrity but no impact on availability. Apache HTTP Server 2.4.66 includes a fix that properly neutralizes these sequences and prevents environment variable overriding. No public exploits or active exploitation have been reported to date, but the vulnerability poses a risk to web servers running vulnerable versions, especially those hosting CGI applications.

For European organizations, the impact of CVE-2025-65082 can be significant, particularly for those operating critical web infrastructure or legacy systems using vulnerable Apache HTTP Server versions with CGI programs. The vulnerability can lead to partial disclosure of sensitive information or unauthorized modification of CGI program behavior, potentially enabling further attacks such as privilege escalation or data tampering. Organizations in sectors like government, finance, healthcare, and telecommunications, which often rely on Apache HTTP Server for web services, may face increased risk of data breaches or service manipulation. Although availability is not directly impacted, the integrity and confidentiality concerns could undermine trust and compliance with data protection regulations such as GDPR. The lack of required authentication and remote exploitability increases the threat surface, making timely patching essential. Additionally, organizations using custom or third-party CGI scripts are at higher risk due to the reliance on environment variables for input.

To mitigate CVE-2025-65082, European organizations should immediately upgrade Apache HTTP Server to version 2.4.66 or later, where the vulnerability is fixed. In environments where immediate upgrade is not feasible, administrators should audit Apache configuration files for any custom environment variable settings that could override server-calculated variables, especially those passed to CGI programs. Implement strict validation and sanitization of environment variables within CGI scripts to reduce risk. Disable or restrict CGI execution where not necessary to minimize the attack surface. Employ web application firewalls (WAFs) with rules designed to detect and block suspicious environment variable manipulations or injection attempts. Regularly monitor server logs for unusual CGI behavior or environment variable anomalies. Conduct vulnerability scanning and penetration testing focused on CGI interfaces to identify potential exploitation. Finally, maintain an inventory of Apache HTTP Server versions in use across the organization to ensure timely patch management.