CVE-2026-34441

MEDIUM

cpp-httplib: HTTP Request Smuggling via Unconsumed GET Request Body

Title source: cna
STIX 2.1

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.

References (2)

Core 2
Core References

Scores

CVSS v3 4.8
EPSS 0.0020
EPSS Percentile 9.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-444
Status published
Products (1)
yhirose/cpp-httplib < 0.40.0 (2 CPE variants)
Published Mar 31, 2026
Tracked Since Apr 01, 2026