# CVE-2026-76992: Uncontrolled Memory Allocation in CODESYS Gateway Client

> An unauthenticated remote attacker can cause denial of service in CODESYS Gateway Client by triggering excessive memory allocation via a malicious gateway response.

- **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:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-cm9r-92x3-hmfj

## What is CVE-2026-76992?

CVE-2026-76992 is a high-severity denial of service vulnerability in CODESYS Development System 3, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The CODESYS Gateway Client allocates memory based on a size field in a gateway response without enforcing an appropriate upper limit. An unauthenticated remote attacker controlling a malicious gateway can exploit this behavior to trigger excessive memory consumption, resulting in a denial-of-service condition thus leading to a total loss of availablity.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-76992?


## How do I fix CVE-2026-76992?

No fix has been published for CVE-2026-76992 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76992 being exploited?

There is no known exploitation of CVE-2026-76992 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76992 and fix it if it is affected.

What it is: CVE-2026-76992 is a high-severity denial of service vulnerability in CODESYS Development System 3, published on 30 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-2026-76992 in the wild and no public exploit code.

Affected product: CODESYS Development System 3. 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-2026-76992/ (Markdown: https://insights.sbomify.com/CVE-2026-76992/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76992
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76992
- OSV: https://osv.dev/vulnerability/CVE-2026-76992

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-76992/
Summaries are generated and may contain mistakes; the official description above is the record.