---
id: "CVE-2026-94018"
kind: "vulnerability"
aliases: ["CVE-2026-94018"]
title: "Web add-on HTTP server: one malformed PUT frees an uninitialized pointer"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "NetX Duo", "fixed": ["6.5.2.202603"], "affected": ">= 6.4.2, <= 6.5.1.202602", "ecosystem": "vendor"}]
ecosystems: []
tags: ["eclipse-threadx", "embedded", "http-server", "iot", "memory-safety", "netx-duo", "other", "rtos", "web-add-on"]
not_affected_if: ["auth-required", "legacy-http-addon", "no-web-addon", "put-disabled"]
published_at: "2026-10-20T16:17:17+00:00"
first_seen_at: "2026-10-23T21:57:20+00:00"
updated_at: "2026-10-24T00:12:38+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-94018", "first_seen_at": "2026-10-23T21:57:20+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-24T00:12:38+00:00"}]
---

# Web add-on HTTP server: one malformed PUT frees an uninitialized pointer

Eclipse ThreadX NetX Duo's Web add-on HTTP server (_nx_web_http_server_put_process) releases an uninitialized packet pointer when a PUT body exceeds Content-Length (ULONG underflow). Default builds: likely crash (DoS). Builds with NX_DISABLE_ERROR_CHECKING: packet pool corruption. Unauthenticated only if the app registers no auth callback for PUT. Legacy addons/http server is not affected.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:NetX Duo affected >= 6.4.2, <= 6.5.1.202602 fixed 6.5.2.202603

## How to check

Check whether your firmware uses NetX Duo with addons/web (nx_web_http_server.c) compiled in, serves PUT requests, and is a version >= 6.4.2 and <= 6.5.1.202602. Check whether NX_DISABLE_ERROR_CHECKING is defined (higher impact) and whether a PUT authentication callback is registered.

## Fix

Upgrade NetX Duo to 6.5.2.202603. Workarounds: do not serve PUT requests, require authentication for PUT, restrict network access to the HTTP server, and leave NetX Duo error checking enabled (the default).

## Timeline

- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-94018
- 2026-10-24T00:12:38+00:00 analyst — Product is Eclipse ThreadX NetX Duo Web add-on; read vendor GHSA-wjxf-gjm5-jh5q. No exploitation or PoC found (Feedly/VulDB say none); X not searched, niche embedded issue. Vendor CVSS 3.1 is 8.2; CVE record says 8.8 (CVSS 4.0). Severity left unchanged.

## Documents

- [advisory] GHSA-wjxf-gjm5-jh5q NetX Duo Web HTTP server uninitialized packet pointer (PUT) https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wjxf-gjm5-jh5q

## From the sources

The Web add-on's HTTP server dereferences and releases an uninitialized pointer when it detects a `Content-Length` underflow while processing a `PUT` request. The condition is reachable by an unauthenticated remote client with a single malformed request.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_