# CVE-2026-34441: cpp-httplib: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library

CVE-2026-34441 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-34441, released March 31, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-34441
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 31, 2026

## Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the request body. On HTTP/1.1 keep-alive connections, the unread body bytes remain on the TCP stream and are interpreted as the start of a new HTTP request. An attacker can embed an arbitrary HTTP request inside the body of a GET request, which the server processes as a separate request. This issue has been patched in version 0.40.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | cpp-httplib Debian 14 | 0.41.0+ds-3 | [DEBIAN-CVE-2026-34441](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34441.md) | Mar 31, 2026 |
| Linux | cpp-httplib Fedora 43 | 0.48.0-1.fc43 | [FEDORA-2026-1D4BD0354A](https://patchblox.com/security/data/fix/linux/fedora-2026-1d4bd0354a.md) | Jun 24, 2026 |
| Linux | cpp-httplib-devel Fedora 43 | 0.48.0-1.fc43 | [FEDORA-2026-1D4BD0354A](https://patchblox.com/security/data/fix/linux/fedora-2026-1d4bd0354a.md) | Jun 24, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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