CVE-2026-34441
low-risk
Published 2026-03-31
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.
Do I need to act?
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0.04% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.8/10
Medium
NETWORK
/ HIGH complexity
Affected Products (1)
Cpp-Httplib
Affected Vendors
20
/ 100
low-risk
Severity
15/34 · Moderate
Exploitability
0/34 · Minimal
Exposure
5/34 · Minimal