CVE-2026-33745
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).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.26% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-200
- Affected
- yhirose/cpp-httplib
- Source
- security-advisories@github.com
References
- https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-6hrp-7fq9-3qv2Exploit, Mitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.