---
id: CVE-2026-103930
title: cpp-httplib is a C++ header-only HTTP/HTTPS library
summary: >-
  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
  …
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-113
published: '2026-10-14'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T19:17:07.657'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103930'
references:
  - url: >-
      https://github.com/yhirose/cpp-httplib/commit/255c075b82cf9f221e6e607e8e6789e6e2bf4c2a
    label: security-advisories@github.com
  - url: 'https://github.com/yhirose/cpp-httplib/pull/2501'
    label: security-advisories@github.com
  - url: 'https://github.com/yhirose/cpp-httplib/releases/tag/v0.51.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-vq69-f637-8fhr
    label: security-advisories@github.com
tags:
  - nvd
ingestedAt: '2026-10-14T19:49:57.605Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.