---
id: "CVE-2026-85068"
page: "https://infrastack.ai/live/CVE-2026-85068"
kind: "vulnerability"
aliases: ["CVE-2026-85068"]
title: "Network UPS Tools: uninitialized stack bytes leak to a rogue USB UPS"
severity: "low"
cvss: 2.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["homelab", "linux", "network-ups-tools", "package", "self-hosted"]
not_affected_if: ["no-usb-ups", "non-blazer-driver", "version-2.8.6-or-later"]
published_at: "2026-11-05T23:17:00+00:00"
first_seen_at: "2026-11-05T23:48:39+00:00"
updated_at: "2026-11-05T23:49:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85068", "first_seen_at": "2026-11-05T23:48:39+00:00"}]
exploit_sources: []
---

# Network UPS Tools: uninitialized stack bytes leak to a rogue USB UPS

Link for people: https://infrastack.ai/live/CVE-2026-85068 (this .md is for agents)

Network UPS Tools reads status from UPS hardware over USB, and a malicious USB device posing as a Mustek Powermust UPS can receive leftover stack memory during normal polling. The attacker gets a bounded, read-only disclosure of uninitialized memory bytes, with no integrity or availability impact.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed NUT version with `upsd -V` or `upsc -V`, and confirm whether the `blazer_usb` driver with the `ippon` subdriver is in use via `grep -r ippon /etc/nut/`.
- Look for USB UPS devices with vendor ID `0x06da` and product ID `0x0003` using `lsusb`.

## Fix

- Network UPS Tools: move to `2.8.6`, which the sources say is the scheduled fixed version.

## Timeline

- 2026-11-05T23:48:39+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-85068

## Documents

- [advisory] Vendor advisory: github.com https://github.com/networkupstools/nut/security/advisories/GHSA-fjxc-2vpv-mqc8
- [fix] Patch: github.com https://github.com/networkupstools/nut/commit/30d56d4282f823949b40763d5c76461c7dd107b3

## From the sources

Network UPS Tools is a collection of programs which provide a common interface for monitoring and administering UPS, PDU and SCD hardware. From 2.4.2 through 2.8.5, ippon_command in drivers/blazer_usb.c partially initializes char tmp[64] with a short Megatec status query and then passes a fixed eight-byte chunk to usb_control_msg. A malicious firmware-controlled USB device presenting the Mustek Powermust VID 0x06da and Mustek Powermust PID 0x0003 matches blazer_usb_id, selects ippon_subdriver, and can receive the uninitialized trailing stack bytes during normal polling. The disclosure is bounded and read-only, requires physical or supply-chain access to the USB bus, and has no established integrity or availability impact. This issue is scheduled to be fixed in version 2.8.6.

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