Oracle Essbase: Access control flaw allows takeover via TCP
Summary
Oracle Essbase version 21.8.3.0.0 is affected by a security vulnerability in its Security component. An unauthenticated attacker with network access via TCP can compromise the server, which Oracle and the CVE record describe as a possible takeover with high impact on confidentiality, integrity and availability. Exploitation is rated difficult (high attack complexity).
Affected
- Oracle Essbase 21.8.3.0.0 (per CVE record and NVD CPE match)
Fixed in
Unknown. Check the Essbase section of Oracle Critical Patch Update Advisory – October 2026 (https://www.oracle.com/security-alerts/cpuoct2026.html) for the fixed version and patch identifier.
Workaround
Unknown. The CVE record provides no workaround.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total
- No public proof of concept found in the reviewed sources
- Not listed in the CISA KEV catalog per OpenCVE; re-check before closing
Our recommendation
- Check whether any Essbase instance exists and whether it is reachable from the internet, including via VPN or remote access
- Restrict network access to Essbase and its TCP/WebLogic ports to known application servers and admin networks
- Apply the Essbase fix from the October 2026 Critical Patch Update once the fixed version is confirmed in Oracle's advisory
- Monitor the KEV catalog and vendor advisories for changes
- If Essbase is not in use, no action is needed beyond confirming this.
- Unverified: whether a support contract is required to obtain the patch.
- Unverified: the exact role of Essbase in your environment.
- Note: this item is not a top priority unless Essbase is exposed.
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
- NVD / vuln record via OpenCVE app.opencve.io
- VulDB CVE-2026-91647 vuldb.com
- Vulners CVE-2026-91647 vulners.com
- Waratek: Oracle October 2026 CPU waratek.com
- Brandefense: Oracle October 2026 CPU brandefense.io
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 1 Nov 2026, 18:12.
Original description (NVD)
Vulnerability in Oracle Essbase (component: Security). The supported version that is affected is 21.8.3.0.0. Difficult to exploit vulnerability allows unauthenticated attacker with network access via TCP to compromise Oracle Essbase. Successful attacks of this vulnerability can result in takeover of Oracle Essbase. CVSS 3.1 Base Score 8.1 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).
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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