---
id: "CVE-2026-43847"
kind: "vulnerability"
aliases: ["CVE-2026-43847"]
title: "Proprietary protocol lets attackers brute force administrator password without limits"
severity: "high"
cvss: 8.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "ADAM-3600", "fixed": ["2.8.5.0"], "affected": "< 2.8.5.0", "ecosystem": "vendor"}]
ecosystems: []
tags: ["adam-3600", "administrator-login", "advantech", "brute-force", "edgelink", "ics", "infrastructure", "ot", "proprietary-protocol"]
not_affected_if: ["firmware-2.8.5.0-or-later", "protocol-not-network-reachable"]
published_at: "2026-10-20T09:17:11+00:00"
first_seen_at: "2026-10-23T21:57:20+00:00"
updated_at: "2026-10-25T03:34:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43847", "first_seen_at": "2026-10-23T21:57:20+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-25T03:34:57+00:00"}]
---

# Proprietary protocol lets attackers brute force administrator password without limits

Advantech ADAM-3600 EdgeLink RTU: the proprietary protocol has no limit on administrator password attempts, so a network attacker can brute force it, even with SafeEnhancement enabled. Fixed by a lockout after repeated failures.

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

## Affected

- vendor:ADAM-3600 affected < 2.8.5.0 fixed 2.8.5.0

## How to check

Check ADAM-3600 firmware version in the device web UI or EdgeLink; versions below 2.8.5.0 are affected. Check whether the device's proprietary protocol ports (6001/7001 are named in a sibling CVE-2026-43844) are reachable from untrusted networks.

## Fix

Upgrade ADAM-3600 firmware to 2.8.5.0 or later (per CVE record; Advantech's fix adds a lockout: after 5 consecutive failed attempts, a 5-minute wait). Until then, restrict network access to the proprietary protocol ports to trusted admin hosts and use a long random admin password.

## Timeline

- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-43847
- 2026-10-25T03:34:57+00:00 analyst — Advantech ADAM-3600 (ACIRT-261001, item 19, NN-2026-0008); vendor PDF read: fix adds lockout (5 failed attempts -> 5 min wait). Affected 'prior to 2.8.5.0' comes from the CVE record/NVD, not stated in the vendor PDF excerpt I read, so nothing marked verified. No exploitation or PoC found; no x search done (low-profile OT CVE).

## Documents

- [advisory] Advantech: Vulnerabilities Identified in ADAM-3600 (ACIRT-261001) https://advcloudfiles.advantech.com/cms/de8e2d94-10ab-470e-ac6f-d2e5434f4ec4/Security%20Advisory%20PDF%20File/SECURITY-ADVISORY----ADAM-3600.pdf
- [describes] CSA Singapore AL-2026-149: Advantech ADAM-3600 EdgeLink multiple vulnerabilities https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2026-149

## From the sources

A vulnerability in the proprietary protocol could allow an attacker to brute force the administrator password without restrictions, even when the SafeEnhancement feature is enabled.

---

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