CVE-2026-91663

Vulnerability in Oracle Essbase (component: Security)

Risk score: 63/100
CVSS: 9.9 v3.1
Exploit chance (30 days): 0.3%
Published: 20 Oct 2026

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What to know

What it is: 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 T3, IIOP to compromise Oracle Essbase. While the vulnerability is in Oracle Essbase, attacks may significantly impact addi…
Affected: oracle essbase
Fix: Apply the vendor's security update; see the linked advisory.
Exploitation: No known exploitation

Story map

Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

Oracle Essbase: Amber, patch this week. A critical vulnerability in Oracle Essbase's security component allows unauthenticated attackers to compromise the system, potentially leading to a takeover. This is a remotely exploitable vulnerability without the need for login credentials.

The flaws

CVE-2026-91663: Vulnerability in Oracle Essbase (component: Security) (CVSS 9.9 · EPSS 0%)
CVE-2026-91665: Vulnerability in Oracle Essbase (component: Security) (CVSS 9.8 · EPSS 0%)
CVE-2026-91638: Vulnerability in Oracle Essbase (component: Security) (CVSS 9.9 · EPSS 0%)
CVE-2026-91644: Vulnerability in Oracle Essbase (component: Security) (CVSS 9.3 · EPSS 0%)

The fix

Fix: Check the linked advisory for a fix, as none is provided in the record.

Who is exposed: {'product': 'Oracle Essbase', 'version': '21.8.3.0.0'}

Where it stands

No known exploitation

Connects to

Same weakness: Access control flaw (CWE-284). 324 other warnings in 30 days
Same product: Earlier Oracle Essbase warnings. 32 in the last 90 days

Why it is Amber

CVSS 9.9 critical

References

https://www.oracle.com/security-alerts/cpuoct2026.html

Original description

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 T3, IIOP 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 takeover of Oracle Essbase. CVSS 3.1 Base Score 9.9 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).

Last activity 20 Oct 2026. Patch Forecast updates every hour.