cpp-httplib: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library
CVE-2026-21428 is fixed in cpp-httplib on 1 platform by DEBIAN-CVE-2026-21428 (version 0.41.0+ds-3), released January 1, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| cpp-httplib · Debian 14 | 0.41.0+ds-3 | DEBIAN-CVE-2026-21428 | Jan 1, 2026 |
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