# CVE-2020-6086: Denial of service in Allen Bradley

> A specially crafted network request causes a loss of communications in Allen-Bradley Flex IO devices, requiring a physical power cycle to restore service.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Oct 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-gwgq-76m9-ffw6

## What is CVE-2020-6086?

CVE-2020-6086 is a high-severity denial of service vulnerability in Allen Bradley, published on 14 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exploitable denial of service vulnerability exists in the ENIP Request Path Data Segment functionality of Allen-Bradley Flex IO 1794-AENT/B. A specially crafted network request can cause a loss of communications with the device resulting in denial-of-service. An attacker can send a malicious packet to trigger this vulnerability.If the Simple Segment Sub-Type is supplied, the device treats the byte following as the Data Size in words. When this value represents a size greater than what remains in the packet data, the device enters a fault state where communication with the device is lost and a physical power cycle is required.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-6086?

It affects 1 product.


Products: Rockwellautomation Flex I\/O 1794-Aent\/B Firmware.

## How do I fix CVE-2020-6086?

No fix has been published for CVE-2020-6086 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-6086 being exploited?

There is no known exploitation of CVE-2020-6086 in the wild and no public exploit code.

## Other vulnerabilities in Allen Bradley

- [CVE-2020-6087](https://insights.sbomify.com/CVE-2020-6087/): Denial of service in Allen Bradley (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-6086 and fix it if it is affected.

What it is: CVE-2020-6086 is a high-severity denial of service vulnerability in Allen Bradley, published on 14 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-6086 in the wild and no public exploit code.

Affected product: Allen Bradley. 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-2020-6086/ (Markdown: https://insights.sbomify.com/CVE-2020-6086/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6086
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6086
- OSV: https://osv.dev/vulnerability/CVE-2020-6086

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-6086/
Summaries are generated and may contain mistakes; the official description above is the record.