A new Apache HTTP Server vulnerability in the HTTP/2 feature could let attackers take down or potentially compromise sites. If you run Apache with HTTP/2, this matters now more than ever.
What happened
Over the last 24 hours, researchers have disclosed a critical flaw in the Apache HTTP Server’s HTTP/2 module (CVE-2026-23918). The issue can cause denial of service and, in certain configurations, remote code execution. Apache and other vendors are reviewing advisories and releasing patches. Details may evolve as more information becomes available.
Why it matters
Why this matters to you:
- Small businesses and personal sites: a single unpatched server could be a target, leading to downtime or a breach.
- Creators and freelance developers: if you run a site or API behind Apache, your customers may feel the impact of outages.
- IT-minded readers: prepare a quick patch window and ensure you have backups and monitoring in place.
Practical steps you can take now
- Check if your servers are running Apache HTTP Server with HTTP/2 enabled. You can verify loaded modules with apachectl -M or httpd -M depending on your OS.
- Upgrade to the latest Apache HTTP Server version that includes the fix. Use your OS package manager to perform the upgrade (for example, apt-get on Debian/Ubuntu or dnf/yum on RHEL/CentOS).
- If patching immediately isn’t possible, temporarily disable HTTP/2 to mitigate risk. This can usually be done by disabling the http2 module in Apache (for example, a2dismod http2 on Debian-based systems) and restarting the server.
- Review and apply vendor advisories and security bulletins from your distribution and the Apache project for any specific steps or configurations to harden.
- Harden defenses at the edge with your CDN or WAF: enable rate limiting and monitor for unusual HTTP/2 traffic patterns that might indicate exploitation attempts.
- Test changes in a staging environment first, ensure you have good backups, and plan a short maintenance window if needed.
Final thought
Staying on top of patching for critical vulnerabilities is part of running online services. Set a reminder to check for updates, and consider automating checks for new advisories so you’re never left in the dark.