# CVE-2026-49035: Stack-based Buffer Overflow in MZ Automation libIEC61850

> A heap-based buffer overflow in libIEC61850 allows remote code execution when ASLR is disabled, or denial of service otherwise.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/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:** 23 Jul 2026
- **Updated:** 24 Jul 2026
- **Also known as:** GHSA-4r66-gmmr-3ww8

## What is CVE-2026-49035?

CVE-2026-49035 is a critical memory corruption vulnerability in MZ Automation libIEC61850, published on 23 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The affected product is vulnerable to a heap-based buffer overflow via a crafted MMS Initiate request. Remote code execution (RCE) has been demonstrated when ASLR is disabled; memory corruption or denial of service may occur in configurations where ASLR is enabled.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-49035?


## How do I fix CVE-2026-49035?

No fix has been published for CVE-2026-49035 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-49035 being exploited?

There is no known exploitation of CVE-2026-49035 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-49035 and fix it if it is affected.

What it is: CVE-2026-49035 is a critical memory corruption vulnerability in MZ Automation libIEC61850, published on 23 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-2026-49035 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-2026-49035/ (Markdown: https://insights.sbomify.com/CVE-2026-49035/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49035
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49035
- OSV: https://osv.dev/vulnerability/CVE-2026-49035

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-49035/
Summaries are generated and may contain mistakes; the official description above is the record.