Denial of Service in mini_httpd HTTP Request Parser

Executive Summary

CVE-2026-68005 is a denial-of-service vulnerability in mini_httpd versions 1.30 and earlier. It allows remote attackers to cause memory exhaustion by sending specially crafted HTTP requests with unbounded headers. The flaw occurs due to lack of header size limits and a flawed timeout mechanism that resets the alarm timer, enabling attackers to maintain connections indefinitely.

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Detection Guidance

To detect this vulnerability, monitor for unusual memory consumption by mini_httpd processes or unexpected service terminations. Check logs for excessive HTTP request headers or slowloris-like attacks. Use commands like 'ps aux | grep mini_httpd' to identify running instances and 'top -p $(pgrep mini_httpd)' to monitor memory usage. Network traffic analysis tools like tcpdump or Wireshark can capture malformed headers.

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Impact Analysis

This vulnerability can cause service disruption by crashing mini_httpd due to memory exhaustion. In constrained environments like routers or IoT devices with limited RAM (32–256MB), the system may terminate the mini_httpd process via the OOM-killer, making the service unavailable. The attack requires no authentication or privileges.

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Compliance Impact

This DoS vulnerability could impact compliance with GDPR and HIPAA by disrupting availability of services handling personal or health data. GDPR requires ensuring availability of processing systems, while HIPAA mandates access to critical systems. A DoS attack could lead to prolonged downtime, potentially violating these requirements.

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Mitigation Strategies

Immediately deploy a reverse proxy like nginx with header size limits (e.g., 'large_client_header_buffers 4 64k;'). Rate-limit connections using iptables or fail2ban. If possible, update mini_httpd to enforce a 64KB header limit and remove the alarm timer reset. Consider migrating to actively maintained alternatives like nginx or lighttpd.

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