CVE-2025-66577 Details
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.
A vulnerability in cpp-httplib versions prior to 0.27.0 allows attacker-controlled HTTP headers to manipulate server-visible metadata, logging, and authorization decisions. The issue arises because the library accepts X-Forwarded-For and X-Real-IP headers without validation, enabling log poisoning and audit evasion by spoofing client IP addresses. This vulnerability is particularly impactful as it disrupts the integrity of access and error logs, which can be exploited to evade detection or mislead investigations.
Users can update to cpp-httplib version 0.27.0 or later, where this vulnerability has been fixed. After updating, verify that the server no longer accepts untrusted headers that can overwrite internal metadata or client IP information.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Dec 5, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/yhirose/cpp-httplib/commit/ac9ebb0ee333ce8bf13523f487bdfad9518a2aff | [email protected] | Patch |
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-gfpf-r66f-5mh2 | [email protected] | ExploitThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-117 | Improper Output Neutralization for Logs | [email protected] |
| CWE-807 | Reliance on Untrusted Inputs in a Security Decision | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| yhirose cpp-httplib | < 0.27.0 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Dec 11, 2025 | Initial Analysis | [email protected] |
| Dec 5, 2025 | New CVE Received | [email protected] |