CVE-2025-58098 is a vulnerability identified in Apache HTTP Server versions up to 2.4.65, specifically affecting configurations where Server Side Includes (SSI) are enabled alongside the mod_cgid module (but not mod_cgi). The vulnerability arises because the server passes the shell-escaped query string directly to the #exec cmd="..." SSI directives. This behavior allows sensitive information to be inserted into the data sent by the server, violating confidentiality and potentially integrity. The CWE classification is CWE-201, indicating insertion of sensitive information into sent data. The vulnerability is exploitable remotely (AV:N), with low attack complexity (AC:L), but requires privileges (PR:L) to configure or influence SSI directives. No user interaction is needed (UI:N), and the scope remains unchanged (S:U). The CVSS v3.1 base score is 8.3, reflecting high severity due to the high confidentiality and integrity impacts and limited availability impact. Although no known exploits are currently in the wild, the vulnerability poses a significant risk if exploited, potentially allowing attackers to leak sensitive data or manipulate server responses. The issue was reserved in August 2025 and published in December 2025. The recommended remediation is to upgrade to Apache HTTP Server version 2.4.66, which addresses this flaw. Organizations should also audit their use of SSI and mod_cgid to minimize exposure.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive information processed or generated by Apache HTTP Server instances, especially those using SSI with mod_cgid. This can compromise confidentiality and integrity of web applications and data, potentially exposing internal server details, user data, or authentication tokens. The impact is particularly critical for sectors relying heavily on Apache HTTP Server for web hosting, such as government, finance, healthcare, and critical infrastructure. Exploitation could facilitate further attacks, including privilege escalation or lateral movement within networks. The limited availability impact means denial of service is less likely, but data leakage and integrity compromise pose serious risks to compliance with GDPR and other data protection regulations. Organizations may face reputational damage, regulatory fines, and operational disruptions if exploited.

1. Upgrade all Apache HTTP Server instances to version 2.4.66 or later immediately to apply the official patch. 2. Audit server configurations to identify and disable Server Side Includes (SSI) where not strictly necessary, especially in combination with mod_cgid. 3. Where SSI is required, consider disabling mod_cgid and using mod_cgi if possible, as the vulnerability does not affect mod_cgi. 4. Implement strict access controls and monitoring on web server configurations to prevent unauthorized changes to SSI directives. 5. Conduct thorough code and configuration reviews to ensure no sensitive data is inadvertently exposed via SSI #exec directives. 6. Employ web application firewalls (WAFs) with rules to detect and block suspicious query strings or command injection attempts related to SSI. 7. Monitor logs for unusual activity involving SSI execution or mod_cgid usage. 8. Educate system administrators on the risks of enabling SSI and mod_cgid together and enforce change management policies.