CVE-2026-34441 cpp-httplib: HTTP Request Smuggling via Unconsumed GET Request Body
Attackers can smuggle arbitrary HTTP requests via unconsumed GET bodies in cpp-httplib, potentially bypassing security controls or executing code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34441?
CVE-2026-34441 is a medium-severity vulnerability in yhirose cpp-httplib, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-444
Which versions are affected by CVE-2026-34441?
It affects 1 product.
Products include Yhirose Cpp-Httplib.
How do I fix CVE-2026-34441?
Upgrade to a fixed version.
Is CVE-2026-34441 being exploited?
There is no known exploitation of CVE-2026-34441 in the wild and no public exploit code.
Other vulnerabilities in yhirose cpp-httplib
- CVE-2025-66570 cpp-httplib Untrusted HTTP Header Handling: Internal Header Shadowing (REMOTE*/LOCAL*)
- CVE-2026-45372 cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection
- CVE-2026-46527 Null dereference in cpp-httplib
- CVE-2026-32627 cpp-httplib has a Silent TLS Certificate Verification Bypass on HTTPS Redirect via Proxy
- CVE-2026-22776 cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb
Sources
Also known as DEBIAN-CVE-2026-34441, GHSA-jv63-rm9j-6jwc, UBUNTU-CVE-2026-34441.