# CVE-2026-9637: CompactLogix® 5380 / ControlLogix® 5580 - Multiple Vulnerabilities

> Attackers can cause a major nonrecoverable fault in Rockwell Logix controllers by sending malformed CIP messages, requiring a power cycle to recover.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Sep 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-q93h-wjgg-gqf8

## What is CVE-2026-9637?

CVE-2026-9637 is a high-severity denial of service vulnerability in Rockwell Automation CompactLogix® 5380 / ControlLogix® 5580, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A denial-of-service security issue exists in the affected Logix platforms listed in the table above. The security issue stems from improper validation of input length during CIP message processing. This can result in a major nonrecoverable fault (MNRF), requiring a power cycle to recover

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-9637?


## How do I fix CVE-2026-9637?

No fix has been published for CVE-2026-9637 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9637 being exploited?

There is no known exploitation of CVE-2026-9637 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9637 and fix it if it is affected.

What it is: CVE-2026-9637 is a high-severity denial of service vulnerability in Rockwell Automation CompactLogix® 5380 / ControlLogix® 5580, published on 1 Sep 2026. 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-2026-9637 in the wild and no public exploit code.

Affected product: Rockwell Automation CompactLogix® 5380 / ControlLogix® 5580. 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-2026-9637/ (Markdown: https://insights.sbomify.com/CVE-2026-9637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9637
- OSV: https://osv.dev/vulnerability/CVE-2026-9637

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9637/
Summaries are generated and may contain mistakes; the official description above is the record.