CVE-2025-66570
10.0 · CRITICALOverview
CVE-2025-66570 is a critical-severity vulnerability affecting yhirose cpp-httplib. It was published on December 5, 2025 and has a CVSS 3.1 base score of 10.0 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 10.0, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and authorization decisions. An attacker can inject headers named REMOTE_ADDR, REMOTE_PORT, LOCAL_ADDR, LOCAL_PORT that are parsed into the request header multimap via read_headers() in httplib.h (headers.emplace), then the server later appends its own internal metadata using the same header names in Server::process_request without erasing duplicates. Because Request::get_header_value returns the first entry for a header key (id == 0) and the client-supplied headers are parsed before server-inserted headers, downstream code that uses these header names may inadvertently use attacker-controlled values. Affected files/locations: cpp-httplib/httplib.h (read_headers, Server::process_request, Request::get_header_value, get_header_value_u64) and cpp-httplib/docker/main.cc (get_client_ip, nginx
Remediation
Check the references section for vendor advisories and patches from yhirose. Update cpp-httplib to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| yhirose | cpp-httplib | >= 0, < 0.27.0 | Affected |
Frequently Asked Questions
What is CVE-2025-66570?
CVE-2025-66570 is a critical-severity vulnerability affecting yhirose cpp-httplib. It was published on December 5, 2025 and has a CVSS 3.1 base score of 10.0 (CRITICAL).
How severe is CVE-2025-66570?
This vulnerability has a CVSS 3.1 base score of 10.0, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-66570?
Check the references section for vendor advisories and patches from yhirose. Update cpp-httplib to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-66570?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-66570 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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