CVE-2025-43859

CRITICAL

Pypi H11 < 0.16.0 - HTTP Request Smuggling

Title source: rule
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2025-43859. PoCs published by manus-use.

AI-analyzed exploit summary This repository contains functional exploit code for CVE-2025-32433, an Erlang OTP SSH vulnerability, demonstrating pre-authentication remote command execution via crafted SSH packets. The PoC includes a Dockerized vulnerable environment and a Python script to trigger the exploit.

Description

h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.

Exploits (1)

github WORKING POC
by manus-use · postscriptpoc
https://github.com/manus-use/cve-pocs/tree/main/h11-CVE-2025-43859

This repository contains functional exploit code for CVE-2025-32433, an Erlang OTP SSH vulnerability, demonstrating pre-authentication remote command execution via crafted SSH packets. The PoC includes a Dockerized vulnerable environment and a Python script to trigger the exploit.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Erlang OTP SSH (OTP-22.3.4.17)
No auth needed
Prerequisites: network access to target SSH port · vulnerable Erlang OTP version
devstral-2 · analyzed Feb 27, 2026 Full analysis →

Scores

CVSS v3 9.1
EPSS 0.0024
EPSS Percentile 47.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-444
Status published
Products (2)
pypi/h11 0 - 0.16.0PyPI
python-hyper/h11 < 0.16.0
Published Apr 24, 2025
Tracked Since Feb 18, 2026