# CVE-2026-80156: Lantronix Autonomous Out-of-Band Devices Arbitrary File Write via Upload Filename Validation Bypass

> Authenticated attackers can bypass filename validation to write arbitrary files, leading to remote code execution on Lantronix out-of-band devices.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-hmch-26g2-q5qx

## What is CVE-2026-80156?

CVE-2026-80156 is a critical path traversal vulnerability in LANTRONIX EMG7500, published on 22 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Lantronix SLC8000 before firmware v9.7.0.5, SLC9000 before firmware v9.7.0.2, EMG8500/EMG7500 before firmware v9.7.0.1, and all firmware versions of SLB882/SLCx-03/SLCx-02 contain a path traversal vulnerability in the web management portal upload endpoint that allows authenticated attackers to write arbitrary data to any location on the device's filesystem, leading to remote code execution. The upload filename validation strips backslash characters but does not subsequently check for forward slashes when a backslash is detected; by supplying a filename containing both characters an attacker writes outside the intended upload directory to any writable path. Attackers can use this vulnerability to achieve complete loss of confidentiality, integrity, and availability on the affected device and potentially impact downstream serial-connected devices.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-80156?


## How do I fix CVE-2026-80156?

No fix has been published for CVE-2026-80156 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-80156 being exploited?

There is no known exploitation of CVE-2026-80156 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80156 and fix it if it is affected.

What it is: CVE-2026-80156 is a critical path traversal vulnerability in LANTRONIX EMG7500, published on 22 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80156 in the wild and no public exploit code.

Affected product: LANTRONIX EMG7500. 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-2026-80156/ (Markdown: https://insights.sbomify.com/CVE-2026-80156/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80156
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80156
- OSV: https://osv.dev/vulnerability/CVE-2026-80156

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80156/
Summaries are generated and may contain mistakes; the official description above is the record.