Zero Radar
← feed
CriticalVulnerabilityCVE-2026-91663updated 25 Oct 2026, 18:50 UTC

Oracle Essbase can be fully taken over by a low-privileged user over the network

Someone who already has a basic login to Oracle Essbase, and can reach it over the network, may be able to take control of the whole system. That could expose or change the data it holds, and may affect other connected products.

Official, 2 sources
SeverityCriticalCVSS 9.9 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-privileged userHas basic login or network access
  2. 2T3 or IIOP requestSent over the network to Essbase
  3. 3Essbase compromisedSecurity flaw lets attacker gain control
  4. 4Scope spreadsOther connected products may be affected
  5. ResultAttacker takes over Oracle Essbase

What happened

A flaw in the Security component of Oracle Essbase 21.8.3.0.0 lets a low-privileged attacker with network access reach the T3 and IIOP protocols and compromise the server. The vulnerability has a scope change, so impact can extend beyond Essbase itself.

Why it is dangerous: A successful attack allows full takeover of Oracle Essbase with high impact to confidentiality, integrity and availability, and can spill over into other products. Organizations running Essbase on the network with any user accounts are at risk.

Are you affected?

You are affected if you run Oracle Essbase 21.8.3.0.0 and it is reachable over the network via T3 or IIOP.

Oracle Essbase 21.8.3.0.0

What to do

  1. Check whether you run Oracle Essbase 21.8.3.0.0
  2. Restrict network access to Essbase, especially the T3 and IIOP ports, to trusted hosts only
  3. Review and limit user accounts that have any access to Essbase
  4. Apply the vendor's Oracle Critical Patch Update or fixed version as soon as it is available to you

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-2026-91663 · GHSA-2h6q-c786-w5h5
CVSS
9.9 / 10
EPSS
0.3% 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 can be fully taken over by a low-privileged user over the network · Zero Radar