CVE-2026-34441

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

MEDIUM
6.5
CVSS Score
Published: March 31, 2026 at 09:21 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
1 product affected across 1 vendorCpp Httplib

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.40.0
Affected range stops below 0.40.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-jv63-rm9j-6jwc
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/yhirose/cpp-httplib/releases/tag/v0.40.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-444

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