# CVE-2012-6440: Rockwell Automation ControlLogix PLC Improper Input Validation

> Attackers can bypass web server authentication via MitM or replay attacks to view and alter PLC configuration and diagnostics.

- **Severity:** Critical 9.3 (`AV:N/AC:M/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Jan 2013
- **Updated:** 3 Jun 2026
- **Also known as:** GHSA-c3p8-qp2x-9xxf

## What is CVE-2012-6440?

CVE-2012-6440 is a critical authentication bypass vulnerability in Rockwell Automation 1756-ENBT, 1756-EWEB, 1768-ENBT, 1768-EWEB communication modules, published on 24 Jan 2013. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Web server password authentication mechanism used by the products is vulnerable to a MitM and Replay attack. Successful exploitation of this vulnerability will allow unauthorized access of the product’s Web server to view and alter product configuration and diagnostics information.

Rockwell Automation EtherNet/IP products; 1756-ENBT, 1756-EWEB, 1768-ENBT, and 1768-EWEB communication modules; CompactLogix L32E and L35E controllers; 1788-ENBT FLEXLogix adapter; 1794-AENTR FLEX I/O EtherNet/IP adapter; ControlLogix 18 and earlier; CompactLogix 18 and earlier; GuardLogix 18 and earlier; SoftLogix 18 and earlier; CompactLogix controllers 19 and earlier; SoftLogix controllers 19 and earlier; ControlLogix controllers 20 and earlier; GuardLogix controllers 20 and earlier; and MicroLogix 1100 and 1400

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2012-6440?

It affects 17 products.


Products: Rockwellautomation 1756-Enbt, Rockwellautomation 1756-Eweb, Rockwellautomation 1768-Enbt, Rockwellautomation 1768-Eweb, Rockwellautomation 1794-Aentr Flex I\/O Ethernet\/Ip Adapter, Rockwellautomation Compactlogix, Rockwellautomation Compactlogix Controllers, Rockwellautomation Compactlogix L32e Controller, Rockwellautomation Compactlogix L35e Controller, Rockwellautomation Controllogix, Rockwellautomation Controllogix Controllers, Rockwellautomation Flexlogix 1788-Enbt Adapter, Rockwellautomation Guardlogix, Rockwellautomation Guardlogix Controllers, Rockwellautomation Micrologix, Rockwellautomation Softlogix, Rockwellautomation Softlogix Controllers.

## How do I fix CVE-2012-6440?

No fix has been published for CVE-2012-6440 yet. Limit exposure of the affected software until one is available.

## Is CVE-2012-6440 being exploited?

There is no known exploitation of CVE-2012-6440 in the wild and no public exploit code.

## Other vulnerabilities in Rockwell Automation 1756-ENBT, 1756-EWEB, 1768-ENBT, 1768-EWEB communication modules

- [CVE-2012-6437](https://insights.sbomify.com/CVE-2012-6437/): Rockwell Automation ControlLogix PLC Improper Authentication (critical 10.0)
- [CVE-2012-6439](https://insights.sbomify.com/CVE-2012-6439/): Rockwell Automation ControlLogix PLC Improper Access Control (high 8.5)
- [CVE-2012-6435](https://insights.sbomify.com/CVE-2012-6435/): Rockwell Automation ControlLogix PLC Improper Access Control (high 7.8)
- [CVE-2012-6436](https://insights.sbomify.com/CVE-2012-6436/): Rockwell Automation ControlLogix PLC Improper Input Validation (high 7.8)
- [CVE-2012-6438](https://insights.sbomify.com/CVE-2012-6438/): Rockwell Automation ControlLogix PLC Improper Input Validation (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-6440 and fix it if it is affected.

What it is: CVE-2012-6440 is a critical authentication bypass vulnerability in Rockwell Automation 1756-ENBT, 1756-EWEB, 1768-ENBT, 1768-EWEB communication modules, published on 24 Jan 2013. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2012-6440 in the wild and no public exploit code.

Affected product: Rockwell Automation 1756-ENBT, 1756-EWEB, 1768-ENBT, 1768-EWEB communication modules. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2012-6440/ (Markdown: https://insights.sbomify.com/CVE-2012-6440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-6440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-6440
- OSV: https://osv.dev/vulnerability/CVE-2012-6440

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From sbomify Insights: https://insights.sbomify.com/CVE-2012-6440/
Summaries are generated and may contain mistakes; the official description above is the record.