A high-severity vulnerability has been discovered in Apache HTTP Server 2, a widely used web server software. This flaw could allow a remote, unauthenticated attacker to execute arbitrary code on the server, potentially leading to a complete system compromise, data theft, or service disruption. Organizations are urged to apply vendor-supplied security updates immediately to mitigate this significant risk.

This vulnerability is a request smuggling flaw in the handling of HTTP/2 Cleartext (h2c) protocol upgrades. An unauthenticated, remote attacker can send a specially crafted HTTP/1.1 request that includes a malicious, embedded secondary request. Due to improper validation during the protocol switch to h2c, the server fails to correctly delineate the boundary between the initial and smuggled requests, causing a desynchronization that can be used to bypass security controls, poison web caches, or achieve remote code execution on the underlying server.

This is a High severity vulnerability with a CVSS score of 8.3, posing a significant threat to business operations. Successful exploitation could lead to a complete compromise of the affected web server, allowing an attacker to steal sensitive data (e.g., customer information, intellectual property), modify or delete critical data, or use the server to launch further attacks against the internal network. The potential consequences include severe reputational damage, financial loss from downtime or data breach recovery, and potential regulatory fines.

Immediate Action: Apply the security updates provided by the Apache Software Foundation to all affected systems immediately, prioritizing internet-facing servers. After patching, restart the Apache service to ensure the update is fully applied.

Proactive Monitoring: Review Apache access and error logs for unusually malformed HTTP/1.1 Upgrade requests or unexpected responses that could indicate exploitation attempts. Monitor network traffic for anomalous outbound connections from web servers, which could signify a successful compromise. Utilize security information and event management (SIEM) systems to correlate log data and alert on suspicious patterns.

Compensating Controls: If immediate patching is not feasible, consider implementing the following controls:

• Disable the h2c protocol upgrade functionality if it is not required for business operations.
• Deploy a Web Application Firewall (WAF) with up-to-date rulesets capable of detecting and blocking HTTP request smuggling attack patterns.
• Enforce strict request validation on upstream proxies or load balancers to normalize and sanitize HTTP requests before they reach the Apache server.

Public Exploit Available: false

Given the High severity (CVSS 8.3) of this remote code execution vulnerability, immediate and decisive action is required. All organizations utilizing Apache HTTP Server 2 must prioritize the deployment of vendor-provided security patches. Although CVE-2025-58098 is not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog, its critical impact warrants treating it with the highest urgency. While the patching process is underway, implement the recommended monitoring and compensating controls to reduce the window of opportunity for attackers.