# CVE-2026-35226: Out-of-bounds Write in CODESYS PROFINET Controller

> An unauthenticated attacker can cause a denial of service by sending malformed PROFINET data to trigger an out-of-bounds write and stop the PLC application.

- **Severity:** High 7.1 (`CVSS:4.0/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jul 2026
- **Updated:** 29 Jul 2026
- **Also known as:** GHSA-jxhr-7f6w-54g7

## What is CVE-2026-35226?

CVE-2026-35226 is a high-severity memory corruption vulnerability in CODESYS PROFINET, published on 29 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An out‑of‑bounds write vulnerability in the CODESYS PROFINET Controller allows an unauthenticated attacker on the same network segment to send malformed PROFINET communication data that triggers an exception in the affected PLC application. The exception is handled by the CODESYS Control runtime system and results in a controlled stop of the PLC application.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-35226?


## How do I fix CVE-2026-35226?

No fix has been published for CVE-2026-35226 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-35226 being exploited?

There is no known exploitation of CVE-2026-35226 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35226 and fix it if it is affected.

What it is: CVE-2026-35226 is a high-severity memory corruption vulnerability in CODESYS PROFINET, published on 29 Jul 2026. 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-2026-35226 in the wild and no public exploit code.

Affected product: CODESYS PROFINET. 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-2026-35226/ (Markdown: https://insights.sbomify.com/CVE-2026-35226/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35226
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35226
- OSV: https://osv.dev/vulnerability/CVE-2026-35226

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35226/
Summaries are generated and may contain mistakes; the official description above is the record.