CVE-2026-34441: cpp-httplib: HTTP Request Smuggling via Unconsumed GET Request Body
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
cpp-httplibto a version that resolves this vulnerability.Fixed in 0.40.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34441?
CVE-2026-34441 is classified as a high-severity vulnerability due to its potential for enabling HTTP Request Smuggling attacks.
How do I fix CVE-2026-34441?
To fix CVE-2026-34441, upgrade cpp-httplib to version 0.40.0 or later.
What type of vulnerability is CVE-2026-34441?
CVE-2026-34441 is an HTTP Request Smuggling vulnerability affecting cpp-httplib.
Who is affected by CVE-2026-34441?
All users of cpp-httplib versions prior to 0.40.0 are affected by CVE-2026-34441.
What can attackers do with CVE-2026-34441?
Attackers can exploit CVE-2026-34441 to perform HTTP Request Smuggling attacks, potentially gaining unauthorized access or manipulating requests.