---
id: "CVE-2026-43837"
kind: "vulnerability"
aliases: ["CVE-2026-43837"]
title: "Password verification buffer overflow lets guest-authenticated attacker run code"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "ADAM-3600 EdgeLink", "fixed": ["2.8.5.0"], "affected": "< 2.8.5.0", "ecosystem": "vendor"}]
ecosystems: []
tags: ["adam-3600", "advantech", "edgelink", "firmware", "ics", "other", "rtu"]
not_affected_if: ["firmware-2.8.5.0-or-later", "no-guest-account", "not-network-reachable"]
published_at: "2026-10-20T09:17:10+00:00"
first_seen_at: "2026-10-23T21:57:20+00:00"
updated_at: "2026-10-25T03:37:19+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43837", "first_seen_at": "2026-10-23T21:57:20+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-25T03:37:19+00:00"}]
---

# Password verification buffer overflow lets guest-authenticated attacker run code

Buffer overflow in the password verification function of Advantech ADAM-3600 EdgeLink (industrial remote terminal unit) firmware before 2.8.5.0. An attacker with a guest login can reach it over the network and achieve code execution. Part of a batch of 30 ADAM-3600 CVEs fixed together. No exploitation reported.

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

## Affected

- vendor:ADAM-3600 EdgeLink affected < 2.8.5.0 fixed 2.8.5.0

## How to check

Check the EdgeLink firmware version on each ADAM-3600 (device web UI / system info). Anything below 2.8.5.0 is affected. Also check whether guest accounts are enabled and whether the device is reachable from untrusted networks.

## Fix

Update ADAM-3600 EdgeLink firmware to 2.8.5.0 or later (Advantech released 2026-10-15; some Advantech text refers to 2.8.5.1, so prefer the newest build from the Advantech ACIRT-261001 advisory). Until then: disable guest accounts, keep RTUs off the internet, and firewall them.

## Timeline

- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-43837
- 2026-10-25T03:37:19+00:00 analyst — Product identified via NVD API: Advantech ADAM-3600 EdgeLink RTU, affected < 2.8.5.0 (NVD, CSA SG, Canada Cyber Centre); Advantech advisory ACIRT-261001 item 9 (NN-2025-0133) confirms the bug and says fix is bounds validation. Part of a 30-CVE batch (43829-43858). Version caveat: Advantech PDF and a third-party page mention 2.8.5.1 for other items, so confirm the exact fixed build with Advantech. No exploitation or PoC found; not verified any field (fixed version only seen on NVD/CSA/CCCS, not stated in vendor text I read).

## 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
- [mentions] Canadian Cyber Centre AV26-1065: Advantech ADAM-3600 prior to v2.8.5.0 https://www.cyber.gc.ca/en/alerts-advisories/control-systems-advantech-security-advisory-av26-1065

## From the sources

A buffer overflow vulnerability in the password verification functionality could allow an attacker with guest authentication to achieve code execution.

---

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