CVE-2024-47252 is a vulnerability classified under CWE-150 (Improper Neutralization of Escape, Meta, or Control Sequences) affecting Apache HTTP Server versions 2.4.63 and earlier. The issue arises in the mod_ssl module, which handles SSL/TLS connections. Specifically, when server administrators configure logging using the CustomLog directive with format specifiers "%{varname}x" or "%{varname}c" to capture mod_ssl variables such as SSL_TLS_SNI, the server fails to properly escape or sanitize user-supplied data before writing it to log files. This lack of escaping allows an attacker controlling the SSL/TLS client to inject escape sequences or control characters into the logs. Such injection can corrupt log integrity, potentially enabling log forging, evasion of detection, or misleading forensic analysis. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS v3.1 score is 7.5 (high), reflecting the ease of exploitation (network vector, low complexity) and the high confidentiality impact due to possible log manipulation. No known exploits have been reported in the wild yet, and no official patches are linked in the provided data, suggesting that mitigation may currently rely on configuration changes or awaiting vendor updates.

For European organizations, this vulnerability poses a significant risk to the integrity and reliability of security logs, which are critical for incident detection, response, and compliance with regulations such as GDPR and NIS Directive. Log injection can lead to falsified or misleading log entries, complicating forensic investigations and potentially allowing attackers to cover their tracks. This undermines trust in security monitoring systems and may delay detection of breaches. Organizations relying heavily on Apache HTTP Server 2.4.x with mod_ssl and custom logging configurations that include SSL/TLS variables are particularly at risk. Critical infrastructure providers, financial institutions, and public sector entities in Europe that depend on accurate logging for regulatory compliance and security monitoring could face increased operational risk. Although availability and integrity of the server itself are not directly impacted, the confidentiality and trustworthiness of log data are compromised, which can have cascading effects on security posture and incident management.

European organizations should immediately audit their Apache HTTP Server configurations to identify usage of CustomLog directives with "%{varname}x" or "%{varname}c" format specifiers that log mod_ssl variables such as SSL_TLS_SNI. Until an official patch is available, administrators should consider disabling logging of these variables or implementing manual sanitization of input data before logging. Employing log management solutions that can detect and filter suspicious escape sequences in logs can help mitigate exploitation impact. Monitoring logs for anomalous entries containing escape characters or control sequences is recommended. Additionally, organizations should plan to apply vendor patches promptly once released. Network-level controls such as restricting access to the Apache HTTP Server to trusted clients and employing TLS client authentication can reduce exposure. Finally, integrating log integrity verification mechanisms and alerting on unexpected log modifications can enhance detection capabilities.