CVE-2026-34441
cpp-httplib: HTTP Request Smuggling via Unconsumed GET Request Body
CVSS Score
4.8
EPSS Score
0.0%
EPSS Percentile
8th
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.
| CWE | CWE-444 |
| Vendor | yhirose |
| Product | cpp-httplib |
| Published | Mar 31, 2026 |
| Last Updated | Apr 1, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
yhirose / cpp-httplib
< 0.40.0