CVE-2026-46527 Details
Description
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector—undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0.
A denial-of-service vulnerability has been identified in cpp-httplib versions prior to 0.44.0. When the server's trusted-proxy list is non-empty, an attacker can send an HTTP request with an X-Forwarded-For header that contains no valid IP segments. This leads to the execution of the get_client_ip() function, which calls front() on an empty std::vector, causing undefined behavior in C++. Typically, this results in an abnormal termination of the process. However, if Sanitizers are enabled, a runtime diagnostic is provided.
Users can update to cpp-httplib version 0.44.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 1, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g | CISA-ADP | ExploitMitigationVendor Advisory |
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-476 | NULL Pointer Dereference | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| yhirose cpp-httplib | < 0.44.0 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 22, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 1, 2026 | Initial Analysis | [email protected] |
| Jun 1, 2026 | CVE Modified | CISA-ADP |
| May 29, 2026 | New CVE Received | [email protected] |