# CVE-2026-50103: Improper Handling of Syntactically Invalid Structure in MZ Automation libIEC61850

> A network-adjacent attacker can crash a subscribing application by sending a crafted GOOSE frame with a malformed TLV value.

- **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:** 23 Jul 2026
- **Updated:** 24 Jul 2026
- **Also known as:** GHSA-mg79-w9qx-hwj2

## What is CVE-2026-50103?

CVE-2026-50103 is a high-severity vulnerability in MZ Automation libIEC61850, published on 23 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A NULL pointer dereference in the L2 GOOSE and R-GOOSE shared parser, which may allow a network-adjacent attacker to crash a subscribing application by sending a crafted GOOSE frame containing a malformed TLV value.

Weakness: CWE-228 (Improper Handling of Syntactically Invalid Structure)

## Which versions are affected by CVE-2026-50103?


## How do I fix CVE-2026-50103?

No fix has been published for CVE-2026-50103 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-50103 being exploited?

There is no known exploitation of CVE-2026-50103 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50103 and fix it if it is affected.

What it is: CVE-2026-50103 is a high-severity vulnerability in MZ Automation libIEC61850, published on 23 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-2026-50103 in the wild and no public exploit code.

Affected product: MZ Automation 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-2026-50103/ (Markdown: https://insights.sbomify.com/CVE-2026-50103/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50103
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50103
- OSV: https://osv.dev/vulnerability/CVE-2026-50103

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50103/
Summaries are generated and may contain mistakes; the official description above is the record.