CVE-2026-21428
High · 7.5CVSS
7.5
EPSS
0.4%
Published
Jan 1, 2026
CISA due date
—
The record
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 packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| openSUSE:Tumbleweed | cpp-httplib | 0 | 0.38.0-1.1 |
Related vulnerabilities
- CVE-2026-46527 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-45372 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-34441 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-33745 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-32627 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-29076 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-28434 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib
- CVE-2026-28435 cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Also affects cpp-httplib