What’s Vulnerable › Vulnerabilities
CVE-2026-33745: cpp-httplib Client Leaks Authentication Credentials to Untrusted Hosts on Cross-Origin HTTP Redirect
- Severity: high (CVSS 7.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-03-27 · updated 2026-06-17
- Weakness: CWE-200
Description
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
How to fix
Upgrade to a fixed version: yhirose cpp-httplib 0.39.0. Check the vendor advisory for mitigations.
References
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