---
title: "CVE-2026-111855: Tektronix 3 Series MDO - Path Traversal"
description: "Tektronix 3 Series MDO < 1.21.1 contains a path traversal caused by insufficient validation of user-supplied file paths in the web management interface, letting remote attackers read arbitrary files, exploit may not require authentication."
url: https://panop.io/threat-heartbeat/CVE-2026-111855/
---

# CVE-2026-111855 Tektronix 3 Series MDO - Path Traversal

Tektronix 3 Series MDO < 1.21.1 contains a path traversal caused by insufficient validation of user-supplied file paths in the web management interface, letting remote attackers read arbitrary files, exploit may not require authentication.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.49% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-111855)

## Details

Type

Path Traversal

Impact

File System Read, Information Disclosure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Published

17 October 2026

Updated

19 October 2026

Weakness

[CWE-22](https://cwe.mitre.org/data/definitions/22.html)

## Vendor fix

Update to version 1.21.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-111855](https://nvd.nist.gov/vuln/detail/CVE-2026-111855)
- [https://download.tek.com/document/TEK-PSA-002-092026.pdf](https://download.tek.com/document/TEK-PSA-002-092026.pdf)
- [https://www.tek.com/en/products/oscilloscopes/3-series-mdo](https://www.tek.com/en/products/oscilloscopes/3-series-mdo)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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