Vulnerability · Published Oct 20, 2026 · Assigned by NCSC.ch
CVE-2026-9589Unblu Spark Authorization Bypass in Configuration Cascade Operations
Critical 9.3
In plain English
A critical-severity missing authorization in Unblu Spark from Unblu inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Official description
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 products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Unblu inc. | Unblu Spark | 7.0 – before 8.37.0 |
Weakness: CWE-862, CWE-639 · Vector: 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
References
- Unblu Security Advisories vendor-advisory