Unrated severityNVD Advisory· Published Dec 5, 2025· Updated Dec 5, 2025
cpp-httplib Untrusted HTTP Header Handling: X-Forwarded-For/X-Real-IP Trust
CVE-2025-66577
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 supply X-Forwarded-For or X-Real-IP headers which get accepted unconditionally by get_client_ip() in docker/main.cc, causing access and error logs (nginx_access_logger / nginx_error_logger) to record spoofed client IPs (log poisoning / audit evasion). This vulnerability is fixed in 0.27.0.
Affected products
1- Range: < 0.27.0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
2- github.com/yhirose/cpp-httplib/commit/ac9ebb0ee333ce8bf13523f487bdfad9518a2affmitrex_refsource_MISC
- github.com/yhirose/cpp-httplib/security/advisories/GHSA-gfpf-r66f-5mh2mitrex_refsource_CONFIRM
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