---
id: CVE-2026-33923
title: Update bundle signature bypass in Guardian/CMC before 26.4.0
summary: >-
  A signature verification vulnerability was discovered in the update
  installation functionality due to inconsistent validation of the update bundle
  contents. An attacker with administrative privileges can remotely supply a
  crafted update …
severity: high
cvss: 7.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-347
vendor: Nozomi Networks
product: Guardian
affected:
  - Guardian < 26.4.0
  - CMC < 26.4.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-29T12:19:57.938573Z'
published: '2026-10-29'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T12:36:53.310Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-33923'
references:
  - url: 'https://security.nozominetworks.com/NN-2026:21-01'
tags:
  - cve.org
epss: 0.00227
epssPercentile: 0.13458
ingestedAt: '2026-11-01T18:59:04.469Z'
---

## Overview

A signature verification vulnerability was discovered in the update installation functionality due to inconsistent validation of the update bundle contents. An attacker with administrative privileges can remotely supply a crafted update bundle that passes signature verification but runs an unsigned script when the bundle is installed. The script runs with root privileges, allowing the attacker to read or modify sensitive data, change the appliance configuration, or shut down the appliance.

## Affected

- `Guardian < 26.4.0`
- `CMC < 26.4.0`

## Remediation

Upgrade to v26.4.0 or later.

### Workarounds

Use internal firewall features to limit access to the web management interface.
Review all accounts with administrative privileges and delete unnecessary ones.
Install update bundles only when they come from trusted Nozomi Networks sources.