CVE-2026-68005 in mini_httpd
Summary
by MITRE • 08/17/2026
An issue in ACME mini_httpd 1.30 and prior allows a remote attacker to cause a denial of service via the HTTP request header parser in the handle_request() function
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/17/2026
The vulnerability identified in ACME mini_httpd versions 1.30 and earlier represents a critical flaw within the web server's core request handling mechanism, specifically located in the handle_request() function. This software is widely deployed due to its lightweight footprint and efficiency in serving static content or simple dynamic pages on resource-constrained systems such as embedded devices, IoT appliances, and legacy infrastructure. The specific defect lies in the HTTP request header parser, which processes incoming network traffic before it reaches application logic. When a remote attacker crafts an HTTP request with malformed or excessively large headers, the parser fails to correctly validate input boundaries or manage memory allocation during parsing operations. This lack of robust validation allows for conditions that lead to resource exhaustion or process termination, effectively crashing the web server instance and rendering it unable to serve legitimate requests until manually restarted.
From a technical perspective, this flaw is characteristic of improper input handling where the software does not adequately check the length, structure, or content of header fields before processing them. In many similar implementations, such vulnerabilities manifest as buffer overflows, integer overflows leading to incorrect memory allocation sizes, or infinite loops triggered by malformed delimiter sequences in headers like Host, User-Agent, or custom extension headers. The absence of strict boundary checks means that a single malicious packet can destabilize the entire service process. This aligns directly with CWE-20 Improper Input Validation and potentially CWE-400 Resource Exhaustion if the flaw leads to memory leaks or CPU spikes during parsing attempts. The vulnerability is exploitable remotely without authentication, allowing any network-accessible client to trigger the denial of service condition simply by sending a specially crafted HTTP request to the affected port.
The operational impact of this vulnerability is severe for organizations relying on mini_httpd for critical services. A successful exploitation results in a complete loss of availability for the hosted web application or API endpoint. For high-traffic sites, even intermittent crashes can lead to significant downtime and revenue loss. In embedded systems where automatic restarts may not be configured or require physical access, the service remains down until an administrator intervenes. This denial of service capability makes mini_httpd a prime target for opportunistic attacks aimed at disrupting network services rather than stealing data. Attackers can use this vulnerability as part of larger distributed denial-of-service campaigns to amplify traffic volume against targets by exploiting multiple vulnerable instances simultaneously.
Mitigation strategies must focus on immediate remediation and long-term architectural improvements. The primary recommendation is to upgrade ACME mini_httpd to a version newer than 1.30, where the handle_request() function has been patched with proper input validation and memory safety checks. If upgrading is not immediately feasible due to compatibility constraints or legacy dependencies, administrators should implement network-level controls such as web application firewalls (WAF) that can detect and block malformed HTTP headers before they reach the server. Rate limiting and connection throttling at the load balancer or reverse proxy layer can also mitigate the impact by preventing a single source from overwhelming the service with repeated malicious requests. Additionally, deploying intrusion detection systems configured to identify patterns associated with header-based attacks provides an additional layer of defense. Long-term, organizations should consider migrating away from mini_httpd in favor of more actively maintained and security-hardened web servers that adhere to modern secure coding standards and undergo regular third-party security audits.