Emergency Patch: Critical RCE Vulnerability in Apache HTTP Server 2.4.67 Threatens Millions of Systems

A critical vulnerability has been identified within the ubiquitous Apache web server, potentially facilitating the complete compromise of affected systems. Although a remediation has been disseminated, administrators are urged to apply the update with the utmost celerity.

The Apache Software Foundation has officially released version 2.4.67 of the Apache HTTP Server. This iteration addresses five distinct vulnerabilities, the most severe of which could lead to remote code execution. Consequently, users operating version 2.4.66 or any antecedent releases are strongly advised to perform an immediate upgrade.

The primary defect, designated as CVE-2026-23918, has garnered a CVSS score of 8.8. This flaw stems from a double-free memory error within the HTTP/2 protocol implementation, specifically triggered during an anomalous connection reset sequence. Such a failure induces memory corruption, empowering an adversary to subvert program execution and invoke arbitrary code upon the server. Notably, this error exclusively impacts version 2.4.66. While the vulnerability was initially disclosed in December 2025 and a patch formulated shortly thereafter, its public integration into a formal release has only just culminated.

The secondary vulnerability, CVE-2026-24072, is classified as a moderate-severity threat residing within the mod_rewrite module—the component responsible for processing redirection rules. A user with authorized access to .htaccess files could potentially read any file residing on the server with the privileges of the httpd process, effectively constituting a privilege escalation vector. This defect affects all versions up to and including 2.4.66.

The remaining three vulnerabilities, while less critical, remain noteworthy. One permits memory overwriting via the mod_proxy_ajp module upon connection to a malicious backend. Another facilitates a denial-of-service condition by overwhelming the server with an excessively large certificate validation response within the mod_md module. The final issue involves a null pointer dereference in mod_dav_lock, which allows an attacker to crash the server through a meticulously crafted request.

The development team advocates for the prompt installation of version 2.4.67 to rectify these systemic weaknesses. In instances where an immediate upgrade is unfeasible, it is prudent to temporarily disable the HTTP/2 protocol and remove the mod_dav_lock module if it is non-essential. Furthermore, auditing access permissions for .htaccess files may serve as a vital mitigation strategy against the exploitation of the secondary flaw.