CVE-2026-33745 Details
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.
A vulnerability in cpp-httplib versions prior to 0.39.0 allows the HTTP client to unintentionally forward stored authentication credentials, including Basic Auth, Bearer Tokens, and Digest Auth, to arbitrary hosts during cross-origin HTTP redirects. This occurs because the client re-attaches these credentials after stripping the Authorization header, resulting in a leak to potentially malicious servers. Additionally, the library lacks proper protection against downgrading HTTPS connections to HTTP, further exposing credentials.
Users are advised to update to cpp-httplib version 0.39.0 or later, and to be cautious of HTTPS-to-HTTP downgrades that could expose credentials.
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 Mar 31, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-6hrp-7fq9-3qv2 | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
| CWE-200 | Exposure of Sensitive Information to an Unauthorized Actor | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| yhirose cpp-httplib | < 0.39.0 |
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 |
| Apr 1, 2026 | Initial Analysis | [email protected] |
| Mar 27, 2026 | New CVE Received | [email protected] |