# CVE-2026-66360: MZ Automation libiec61850 Out-of-bounds Read

> An attacker can cause a denial of service in applications using libiec61850 by sending a crafted TCP connection that triggers an out-of-bounds read.

- **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 Jul 2026
- **Updated:** 31 Jul 2026
- **Also known as:** GHSA-xhv7-j6rr-ph72

## What is CVE-2026-66360?

CVE-2026-66360 is a high-severity denial of service vulnerability in MZ Automation GmbH libiec61850, published on 30 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ISO Presentation layer contains a flaw in the handling of specific 
parameters during normal mode negotiation. A missing length check in the
 processing of the encoded presentation data allows an attacker 
controlled field with a zero length value to trigger a bounded heap over
 read. This condition occurs before MMS session establishment, a crafted
 TCP/102 connection attempt can trigger the issue. The resulting over 
read causes the process to terminate, leading to a denial of service 
condition.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-66360?


## How do I fix CVE-2026-66360?

No fix has been published for CVE-2026-66360 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66360 being exploited?

There is no known exploitation of CVE-2026-66360 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66360 and fix it if it is affected.

What it is: CVE-2026-66360 is a high-severity denial of service vulnerability in MZ Automation GmbH libiec61850, published on 30 Jul 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-2026-66360 in the wild and no public exploit code.

Affected product: MZ Automation GmbH libiec61850. 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-2026-66360/ (Markdown: https://insights.sbomify.com/CVE-2026-66360/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66360
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66360
- OSV: https://osv.dev/vulnerability/CVE-2026-66360

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66360/
Summaries are generated and may contain mistakes; the official description above is the record.