CVE-2026-9589
CRITICALDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
CVSS v4 Vector
Exploitability
Impact
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
Exploit Intelligence
Low risk: more likely to be exploited than 28% of all known CVEs.
References
Related Vulnerabilities
Other CWE-639 (Authorization Bypass Through User-Controlled Key) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-6875 | Critical | 9.8 | 90% | - | - |
| CVE-2024-46982 | High | 7.5 | 59% | - | Fix |
| CVE-2021-45428 | Critical | 9.8 | 57% | - | - |
| CVE-2019-17382 | Critical | 9.1 | 54% | - | Fix |
| CVE-2019-13360 | Critical | 9.8 | 24% | - | - |
| CVE-2023-48783 | Medium | 5.4 | 22% | - | Fix |
Common questions
How do I fix CVE-2026-9589?
No published fix for CVE-2026-9589 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-9589 being actively exploited?
Not that we know of. CVE-2026-9589 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.36% is the estimated probability that it will be exploited in the next 30 days. That is higher than 28% of all scored CVEs.
How severe is CVE-2026-9589?
CVE-2026-9589 has a CVSS v4 base score of 9.3, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-9589
Markdown
[](https://tridentstack.com/cve/CVE-2026-9589)HTML
<a href="https://tridentstack.com/cve/CVE-2026-9589"><img src="https://tridentstack.com/cve/badge/CVE-2026-9589.svg" alt="CVE-2026-9589"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-20.