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Fencer Vulns
medium 4.8

CVE-2026-34441 json

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

published 2026-03-31 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-17672

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

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.

Patch / fix

  • cpp-httplib_project cpp-httplib 0.40.0
  • yhirose cpp-httplib 0.40.0
  • cpp-httplib Debian 14 0.41.0+ds-3

debian advisories DEBIAN-CVE-2026-34441

  • cpp-httplib openSUSE Tumbleweed 0.42.0-1.1

opensuse advisories openSUSE-SU-2026:10573-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-34441 updated cvss 4.8

cpp-httplib: cpp-httplib: HTTP Request Smuggling via unconsumed GET request body

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-jv63-rm9j-6jwc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

  • yhirose cpp-httplib

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.