CVE-2026-9589
Unblu Spark Authorization Bypass in Configuration Cascade Operations
- Published
- Updated
- Reserved
- Assigned by
- NCSC.ch
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NCSC.chCNA (assigner) | 4.0 | Critical9.3 | 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 |
| NCSC.chCNA (assigner) | 4.0 | High8.9 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:H |
| NVDNVD · Deferred | 4.0 | Critical9.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.36% · top 70% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.3.
Weakness
Affected products
- affected 7.0 – < 8.37.0
What to do
Solution: 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.
References (1)
- Unblu Security Advisories (opens in a new tab)vendor-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-9589)Record last updated .