---
id: CVE-2026-9589
title: Unblu Spark Authorization Bypass in Configuration Cascade Operations
summary: >-
  Missing authorization in the configuration cascade operations of the
  Collaboration Server in Unblu inc. Unblu Spark 7.0 through 8.36.1-hotfix.0, on
  on-premises and cloud deployments, allows an authenticated remote attacker to
  read and ch…
severity: critical
cvss: 9.3
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:H'
cvssSource: cna
cwe:
  - CWE-862
  - CWE-639
vendor: Unblu inc.
product: Unblu Spark
affected:
  - unblu_spark >= 7.0 < 8.37.0
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T11:01:14.409Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-9589'
references:
  - url: 'https://docs.unblu.com/latest/security-bulletins/#UBL-2026-002'
    label: Unblu Security Advisories
tags:
  - cve.org
ingestedAt: '2026-10-20T12:05:07.321Z'
---

## Overview

Missing authorization in the configuration cascade operations of the Collaboration Server in Unblu inc. Unblu Spark 7.0 through 8.36.1-hotfix.0, on on-premises and cloud deployments, allows an authenticated remote attacker to read and change configuration properties of entities they aren't authorized to access, including other users, other accounts and, in Unblu Cloud, other customers' accounts, via configuration read and write operations that target those entities.



The Collaboration Server doesn't check whether the user reading or changing configuration has access to the entity the configuration belongs to. With certain non-default configuration validation settings, a registered user can additionally write configuration properties they aren't allowed to edit, in any scope.



Exploitation requires an authenticated session but no user interaction.

## Affected

- `unblu_spark >= 7.0 < 8.37.0`

## Remediation

Upgrade to Unblu Spark 8.37.2 or later. There is no fix for Unblu Spark 7.x.



Unblu Cloud customers needn't take any action. The fix is already deployed in Unblu Cloud.



There is no workaround for on-premises deployments.