Apache Patches Critical HTTP/2 Flaw Allowing Remote Code Execution on Web Servers - CyberSecurityNews
Apache has fixed a critical bug in its HTTP/2 module that could allow remote attackers to execute code on web servers, with the patch released on November 11, 2026.
The vulnerability, tracked as CVE-2026-119618, resides in the assign_headers() function within the mod_http2 module. Apache describes it as a concurrency issue where shared resources are accessed without proper locking mechanisms. This flaw can damage the heap memory area, potentially leading to remote code execution on affected servers.
According to Apache's own impact scale, the "Critical" designation is reserved for vulnerabilities that could enable remote attackers to execute code on servers, potentially allowing exploits to spread automatically like worms.
Discovery Timeline
Anthropic's OSS Scanner discovered the flaw and reported it to Apache on October 26, 2026. Just a week later, on November 3, Anthony Weems and Simon Scannell from Google Cloud Vulnerability Research independently reported the same issue. Apache released the fix on November 11 in version 2.4.71 of the HTTP Server.
The same release closes two more holes. CVE-2026-106023 is rated "important" and sits in mod_md. A NULL pointer error there can crash a child process while it handles a request, and it affects versions 2.4.30 through 2.4.70.
Affected Systems
The vulnerability specifically impacts Apache HTTP Server versions 2.4.55 through 2.4.70. Those running the standalone mod_h2 from GitHub should check versions 2.0.8 through 2.0.42. Servers that handle HTTP/2 traffic are the primary targets since the flaw exists in that specific module.
This latest patch comes shortly after the October release of version 2.4.69, which fixed 20 CVEs, and version 2.4.68 in June, which addressed 13 vulnerabilities. The frequent updates highlight ongoing security challenges in web server implementations.
Mitigation Steps
Apache has not provided a workaround for this vulnerability, making immediate patching the most critical action. Organizations should prioritize upgrading to Apache HTTP Server 2.4.71, starting with public-facing servers that have HTTP/2 enabled. Many Linux distributions may have implemented security fixes without version changes, so administrators should check vendor advisories and package changelogs.
For systems that cannot be upgraded immediately, administrators can limit servers to HTTP/1.1 protocol until patches are applied. However, this temporary measure should be tested first as it may affect performance and client compatibility. Administrators should also monitor server logs for unusual crashes or worker-process restarts, which could indicate probing attempts.
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