CVE-2026-33745: Yhirose Cpp-Httplib

High severity, CVSS 7.4. EPSS: 0.4% chance of exploitation in the next 30 days.

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.39.0, the cpp-httplib HTTP client forwards stored Basic Auth, Bearer Token, and Digest Auth credentials to arbitrary hosts when following cross-origin HTTP redirects (301/302/307/308). A malicious or compromised server can redirect the client to an attacker-controlled host, which then receives the plaintext credentials in the `Authorization` header. Version 0.39.0 fixes the issue.

Affected products

• Yhirose Cpp-Httplib: before 0.39.0 (fixed in 0.39.0)

Published 2026-03-27. Last modified 2026-06-17.