---
id: "CVE-2026-91636"
kind: "vulnerability"
aliases: ["CVE-2026-91636"]
title: "Oracle Essbase: low-privilege HTTP attacker gains access to all accessible data"
severity: "high"
cvss: 7.7
epss: 0.00371
exploited: false
status: "open"
category: "vendor"
products: [{"name": "oracle essbase", "fixed": [], "affected": "= 21.8.3.0.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["oracle-essbase", "self-hosted", "vendor"]
not_affected_if: ["http-restricted", "no-essbase"]
published_at: "2026-10-20T22:21:03+00:00"
first_seen_at: "2026-10-23T21:57:27+00:00"
updated_at: "2026-10-25T03:10:37+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91636", "first_seen_at": "2026-10-23T21:57:27+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91636", "first_seen_at": "2026-10-24T13:15:55+00:00"}]
---

# Oracle Essbase: low-privilege HTTP attacker gains access to all accessible data

Oracle Essbase 21.8.3.0.0 has a security flaw reachable over HTTP that lets an attacker with low-privilege credentials read critical data. The CVSS 3.1 vector shows a scope change, so the impact can reach other products, with high confidentiality impact and no integrity or availability impact.

_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

- Check the installed Essbase version against `21.8.3.0.0`
- Confirm whether Essbase is reachable over HTTP from untrusted networks
- Review the Oracle Critical Patch Update advisory for the fixed build (unknown from these sources)

## Fix

- Apply the Oracle patch for Essbase that addresses this CVE (fixed version unknown from these sources)
- Restrict HTTP access to Essbase to trusted networks until patched

## Timeline

- 2026-10-23T21:57:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91636
- 2026-10-24T13:15:55+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91636

## From the sources

Vulnerability in Oracle Essbase (component: Security).   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. CVSS 3.1 Base Score 7.7 (Confidentiality impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N).

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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_