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The Apache Software Foundation is telling system administrators to act now. A cluster of serious security flaws has been found in the Apache HTTP Server, the worst of which is a Remote Code Execution bug that could let attackers take full control of a vulnerable machine.

Apache runs on roughly a quarter of the active web, so these aren’t obscure edge-case bugs. They’ve all been fixed in the newly released version 2.4.67, and the window to patch before attackers start scanning is shorter than most admins would like.

The short version: Five vulnerabilities were patched, including a high-severity RCE (CVE-2026-23918). Any server on version 2.4.66 or earlier is exposed to varying degrees of risk. The fix is an upgrade to 2.4.67.

Apache Webserver

The Main Threat: CVE-2026-23918 (CVSS 8.8)

The most dangerous bug is a double-free memory corruption flaw in the server’s HTTP/2 implementation.

Here’s how it works: Apache allocates memory to handle an incoming request. An attacker sends a specially crafted “early reset” frame. The server’s memory management logic then tries to free the same memory region twice – a condition known as a double-free. That corrupts the heap and hands the attacker a potential path to redirect how the server executes code.

At minimum, this crashes the server. In a worse scenario, it enables Remote Code Execution.

Worth noting: this specific bug only affects version 2.4.66, not older releases.

Privilege Escalation: CVE-2026-24072

Less dramatic than RCE, but still worth paying attention to. This flaw in mod_rewrite lets a local user who can write .htaccess files read any file on the system using the elevated privileges of the httpd process.

In shared hosting environments, that’s a real problem – a restricted user can effectively access data belonging to other users or read sensitive system files they have no business seeing.

The Other Three Fixes in 2.4.67

Three additional issues were patched:

CVE-2026-28780 (Heap Buffer Overflow in mod_proxy_ajp): A malicious AJP server can overwrite 4 bytes of heap memory. Rated low severity, but it’s a sign that legacy protocol handlers keep accumulating risk.

CVE-2026-29168 (OCSP Resource Exhaustion in mod_md): Oversized OCSP response packets can exhaust server resources, slowing things down or causing a crash.

CVE-2026-29169 (NULL Pointer Dereference in mod_dav_lock): An unauthenticated attacker can crash the server process. This module is mostly used for Subversion support on versions older than 1.2.0, so most modern setups don’t need it at all.

What to Do Right Now

Upgrade to 2.4.67. There’s no substitute here, it’s the only way to fix all five issues. Disable HTTP/2 temporarily if an immediate upgrade isn’t possible. This blocks the RCE vector while you plan the upgrade. Remove mod_dav_lock if you’re not running legacy Subversion. It’s an easy win. Audit who can write .htaccess files. Tighten those permissions to block the privilege escalation bug.

FAQs

Is my server safe if I don’t use HTTP/2? You’re protected from the RCE specifically, but the privilege escalation and DoS bugs in other modules still apply. You still need to upgrade.

How do I check my version? Run httpd -v or apache2 -v in your terminal.

Is this being actively exploited? As of May 5, 2026, no confirmed exploitation has been reported. That said, proof-of-concept code tends to surface quickly after public disclosure, so the clock is ticking.

Where do I get the patch? The official Apache HTTP Server download page has the latest source code and binaries.