Oracle Essbase: Privilege escalation and data access in Federated Partitions
Summary
Oracle Essbase version 21.8.3.0.0 contains a vulnerability in the Federated Partitions component. A remote attacker with network access via HTTP and a low-privileged account can compromise the server, with a scope change to other products. Successful attacks can lead to unauthorized read access to data, unauthorized modification of data and a partial denial of service.
Affected
- Oracle Essbase 21.8.3.0.0
- Other versions: Unknown.
Fixed in
- Unknown. Refer to Oracle's October 2026 Critical Patch Update (CPU289) for the fixed build.
Workaround
- None documented by the CNA or Oracle in the available sources.
- Interim: restrict HTTP access to Essbase to internal or VPN-only networks.
- Interim: review and reduce low-privileged accounts.
Exploitation
- No evidence of exploitation in the wild.
- Not listed in the CISA KEV catalog.
- CISA SSVC: exploitation none, not automatable.
- No public proof-of-concept detected (secondary source, not independently verified).
- EPSS below 1%.
Our recommendation
- Inventory all Oracle Essbase instances and confirm the installed version.
- Apply the October 2026 Oracle Critical Patch Update to all Essbase 21.8.3.0.0 systems without delay and confirm the fixed build via Oracle advisory CPU289.
- Restrict HTTP access to Essbase to internal or VPN-only networks and do not expose it to the internet.
- Review low-privileged accounts and monitor authentication and access logs.
- Note that NVD/CNA lists CVSS 9.1 with CWE-284, while VulDB lists CWE-269 and 9.9.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Oracle Critical Patch Update Advisory October 2026 www.oracle.com
- Oracle Security Blog: October 2026 Critical Patch Update released blogs.oracle.com
- OpenCVE: CVE-2026-91656 app.opencve.io
- VulDB: CVE-2026-91656 vuldb.com
- VulDB: 424463 vuldb.com
- Vulners: CVE-2026-91656 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 05:41.
Original description (NVD)
Vulnerability in Oracle Essbase (component: Federated Partitions). The supported version that is affected is 21.8.3.0.0. Easily exploitable vulnerability allows low privileged attacker with network access via HTTP to compromise Oracle Essbase. While the vulnerability is in Oracle Essbase, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle Essbase accessible data as well as unauthorized update, insert or delete access to some of Oracle Essbase accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Essbase. CVSS 3.1 Base Score 9.1 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L).
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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