7.7
High
CVE-2026-21428 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
Description
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| cpp-httplib 0.30 | earliest → < 0.30.0 | 0.30.0 |
Other CVEs of cpp-httplib
The 24 CVEs of cpp-httplib →
CVE-2026-103930
cpp-httplib is a C++ header-only HTTP/HTTPS library
3.7
Low
CVE-2026-102944
cpp-httplib is a C++ header-only HTTP/HTTPS library
7.5
High
CVE-2026-77358
cpp-httplib is a C++ header-only HTTP/HTTPS library
8.2
High
CVE-2026-77341
cpp-httplib is a C++ header-only HTTP/HTTPS library
5.3
Medium