Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Yhirose | Cpp-Httplib | < 0.44.0 |
Related Weaknesses (CWE)
References
- https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578gExploitMitigationVendor Advisory
- https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578gExploitMitigationVendor Advisory
FAQ
What is CVE-2026-46527?
CVE-2026-46527 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 atta...
How severe is CVE-2026-46527?
CVE-2026-46527 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-46527?
Check the references section above for vendor advisories and patch information. Affected products include: Yhirose Cpp-Httplib.