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CriticalVulnerabilityCVE-2026-91644updated 25 Oct 2026, 18:50 UTC

Oracle Essbase flaw lets unauthenticated attackers access and change data

A weakness in Oracle Essbase, a business data analysis server, can be used by an attacker over the network without logging in. They could read sensitive data and modify some of it, and the damage can spread to other connected products.

Official, 2 sources
SeverityCriticalCVSS 9.3 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. 1Remote attackerNo login or credentials needed
  2. 2HTTP requestSent over the network to Essbase
  3. 3Essbase Security flawFlaw in the Security component is abused
  4. 4Data accessedCritical and accessible data exposed
  5. 5Data changedSome data can be inserted, updated or deleted
  6. ResultAttacker reads and alters Essbase data

What happened

An easily exploitable flaw in the Security component of Oracle Essbase 21.8.3.0.0 allows unauthenticated network attackers using HTTP to compromise the product, with scope change affecting other products.

Why it is dangerous: Attackers could gain unauthorized access to critical data or all Essbase-accessible data, and insert, update or delete some of it. Organizations running Essbase on a network that others can reach are at risk.

Are you affected?

You are affected if you run Oracle Essbase version 21.8.3.0.0 and it is reachable over HTTP from a network an attacker can access.

Oracle Essbase 21.8.3.0.0

What to do

  1. Check whether you run Oracle Essbase 21.8.3.0.0 and whether its HTTP service is reachable from untrusted networks
  2. Restrict network access to Essbase to trusted users and systems only
  3. Check Oracle's security advisory for the patch or mitigation for this issue and apply it as soon as it is available

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-2026-91644 · GHSA-9xf3-7hgg-hxj8
CVSS
9.3 / 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 unauthenticated attackers access and change data · Zero Radar