---
id: "CVE-2026-91646"
kind: "vulnerability"
aliases: ["CVE-2026-91646"]
title: "Oracle Essbase: unauthenticated network flaw exposes some data and partial denial of service"
severity: "medium"
cvss: 5.6
epss: 0.00251
exploited: false
status: "open"
category: "vendor"
products: [{"name": "oracle essbase", "fixed": [], "affected": "= 21.8.3.0.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["java", "on-prem", "oracle-essbase", "vendor"]
not_affected_if: ["no-network-access-to-t3-iiop"]
published_at: "2026-10-20T22:21:04+00:00"
first_seen_at: "2026-10-23T21:57:27+00:00"
updated_at: "2026-10-25T04:10:34+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91646", "first_seen_at": "2026-10-23T21:57:27+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91646", "first_seen_at": "2026-10-24T13:15:55+00:00"}]
---

# Oracle Essbase: unauthenticated network flaw exposes some data and partial denial of service

Oracle Essbase 21.8.3.0.0 has a Security component flaw reachable over the network through the T3 and IIOP protocols. An unauthenticated attacker who can meet the hard-to-exploit conditions can read or change a subset of Essbase data and partially disrupt the service.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:oracle essbase affected = 21.8.3.0.0 fixed ?

## How to check

- Confirm the installed Essbase version is `21.8.3.0.0` (unknown how to read it from the sources)
- Check whether T3 or IIOP listeners are reachable from untrusted networks (unknown exact command in sources)

## Fix

- Apply the Oracle Critical Patch Update fix for Essbase (fixed version: unknown from the sources)
- Restrict network access to Essbase T3 and IIOP ports until patched

## Timeline

- 2026-10-23T21:57:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91646
- 2026-10-24T13:15:55+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91646

## From the sources

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 T3, IIOP to compromise Oracle Essbase.  Successful attacks of this vulnerability can result in  unauthorized update, insert or delete access to some of Oracle Essbase accessible data as well as  unauthorized read access to a subset 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 5.6 (Confidentiality, Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L).

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_