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CVE PROGRAM SOURCE RECORD3.7 Low

CVE-2026-103930

cpp-httplib open_stream serializes CRLF in request target into HTTP request line

Description

cpp-httplib is a C++ header-only HTTP/HTTPS library. From 0.29.0 until 0.51.0, Client::open_stream in httplib.h accepts a caller-controlled path that reaches detail::write_request_line() without the detail::encode_path() protection used by the ordinary buffered request path. Raw carriage-return and line-feed bytes in the path can therefore split the outbound HTTP/1.1 request line and inject attacker-shaped request metadata. Exploitation requires an embedding application to pass remote user input into the open_stream path and a backend or intermediary that interprets the injected bytes; the established impact is modification of backend-visible request data, not direct confidentiality or availability impact. This issue is fixed in version 0.51.0.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

yhirose cpp-httplib

  • >= 0.29.0, < 0.51.0affected

References