---
id: "CVE-2026-105981"
kind: "vulnerability"
aliases: ["CVE-2026-105981"]
title: "Welotec TK100, TK500-v2 and TK500-v3 routers: Digital I/O command injection gives root to an admin"
severity: "high"
cvss: 8.6
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "TK100", "fixed": [], "affected": "< 3.5.116", "ecosystem": "vendor"}, {"name": "TK500-v2", "fixed": [], "affected": "< 1.0.124", "ecosystem": "vendor"}, {"name": "TK500-v3", "fixed": [], "affected": "< 1.0.123", "ecosystem": "vendor"}]
ecosystems: []
tags: ["command-injection", "digital-io", "industrial", "infrastructure", "router", "tk100", "tk500", "welotec"]
not_affected_if: ["auth-required"]
published_at: "2026-11-03T09:17:10+00:00"
first_seen_at: "2026-11-03T09:19:50+00:00"
updated_at: "2026-11-03T09:21:12+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105981", "first_seen_at": "2026-11-03T09:19:50+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-11-03T09:21:12+00:00"}]
---

# Welotec TK100, TK500-v2 and TK500-v3 routers: Digital I/O command injection gives root to an admin

Improper input validation in the Digital I/O function lets a remote attacker with high privileges inject operating system commands. The injected commands run with root privileges.

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

## Affected

- vendor:TK100 affected < 3.5.116 fixed ?
- vendor:TK500-v2 affected < 1.0.124 fixed ?
- vendor:TK500-v3 affected < 1.0.123 fixed ?

## How to check

Check the firmware version in the router's web interface. Affected: TK100 (TK102L, TK102W) below 3.5.116; TK500-v2 (TK525L-v2, TK525L-W-v2, TK525W-v2, TK535L1-v2) below 1.0.124; TK500-v3 (TK525L-v3, TK525L-W-G-v3, TK525L-IO-v3, TK525L-W-v3, TK525W-v3, TK555L-v3) below 1.0.123. Also restrict who can reach the web management interface.

## Timeline

- 2026-11-03T09:19:50+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-105981
- 2026-11-03T09:21:12+00:00 analyst — Found CERT@VDE advisory VDE-2026-119 (Welotec TK routers); affected ranges from advisory. Advisory has no remediation section, so fixed versions are not stated (<N ranges imply but do not say it). No exploitation or PoC found.

## Documents

- [advisory] VDE-2026-119 Welotec: Multiple vulnerabilities in TK routers https://www.certvde.com/en/advisories/VDE-2026-119/
- [describes] CVE record CVE-2026-105981 (CNA CERT@VDE) https://cveawg.mitre.org/api/cve/CVE-2026-105981

## From the sources

Improper input validation in the Digital I/O function may allow a remote attacker with high privileges to inject operating system commands and execute them with root privileges.

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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_