VDB
CVE-2026-21428
CVE-2026-21428
PUBLISHED
CVSS 7.7 HIGH
Reported by GitHub_M · Published January 1, 2026
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the ``write_headers`` function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.
Risk Scores
CVSS 4.0
7.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| yhirose | cpp-httplib | < 0.30.0 |
| yhirose | cpp-httplib | < 0.30.0, < 0.30.0 |
Timeline
- Dec 29, 2025 CVE ID Reserved
- Jan 1, 2026 CVE Published
- Jan 2, 2026 EPSS Score
- Jan 2, 2026 CVE Updated
- Jan 6, 2026 EPSS Score
- Jan 9, 2026 EPSS Score
- Jan 13, 2026 EPSS Score
- Jan 16, 2026 EPSS Score
- Jan 20, 2026 EPSS Score
- Jan 24, 2026 EPSS Score
- Jan 27, 2026 EPSS Score
- Jan 31, 2026 EPSS Score