CVE-2026-91664

Vulnerability in Oracle Essbase (component: Security)

Risk score: 54/100
CVSS: 7.5 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 unauthenticated attacker with network access via TCP to compromise Oracle Essbase. Successful attacks of this vulnerability can result in unauthorized ability to cause a …
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-2026-91664: Vulnerability in Oracle Essbase (component: Security) (CVSS 7.5 · 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: Denial of service (CWE-400). 253 other warnings in 30 days
Same product: Earlier Oracle Essbase warnings. 32 in the last 90 days

Why it is Yellow

CVSS 7.5 high
Remotely exploitable without logging in

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 unauthenticated attacker with network access via TCP to compromise Oracle Essbase. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle Essbase. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

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