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CriticalVulnerabilityCVE-2026-91656updated 25 Oct 2026, 18:50 UTC

Oracle Essbase flaw lets low-privilege users take over data over HTTP

A user with only a basic login on Oracle Essbase (a business data and reporting server) could abuse a flaw in its Federated Partitions feature to read, change, or delete data they should not reach, and knock parts of the service offline. Th

Official, 2 sources
SeverityCriticalCVSS 9.1 of 10
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official, 2 sourcesBacked by an official source

How the attack works simplified

  1. 1Low-privilege userHolds a basic valid login
  2. 2HTTP requestSent over the network to Essbase
  3. 3Federated Partitions flawLets requests exceed intended permissions
  4. 4Essbase dataRead, changed, or deleted without authorization
  5. ResultAttacker gains broad access to Essbase data

What happened

A critical vulnerability in the Federated Partitions component of Oracle Essbase 21.8.3.0.0 allows a low-privileged attacker with HTTP network access to compromise the server, with scope change that can affect additional products.

Why it is dangerous: Successful attacks can expose critical data or all data accessible to Essbase, allow unauthorized updates and deletions, and cause partial denial of service. Organizations running Essbase with Federated Partitions that accept network access are at risk.

Are you affected?

You are affected if you run Oracle Essbase 21.8.3.0.0 with the Federated Partitions component reachable over the network.

Oracle Essbase 21.8.3.0.0 (Federated Partitions component)

What to do

  1. Check whether you run Oracle Essbase 21.8.3.0.0 with Federated Partitions enabled
  2. Apply the fix from Oracle's security advisory or a vendor-supplied patch as soon as it is available
  3. Restrict network access to the Essbase HTTP interface to trusted users and networks until patched
  4. Review user accounts and audit logs for unexpected data changes or access

Timeline

  1. 20 Oct 2026, 22:21 UTC
    Publicly disclosed
  2. 20 Oct 2026, 22:21 UTC
    Reported by NVD · NVD
  3. 25 Oct 2026, 18:50 UTC
    GitHub Advisory reported on it · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-91656 · GHSA-wrf8-v53q-jjvv
CVSS
9.1 / 10
EPSS
0.2% chance of exploitation within 30 days
Disclosed
20 Oct 2026, 22:21 UTC
On Zero Radar
before the radar started
Last change
25 Oct 2026, 18:50 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

Oracle Essbase flaw lets low-privilege users take over data over HTTP · Zero Radar