CVE-2026-91656 Oracle CVE debrief

Who should care

Oracle Essbase administrators and security teams should assess exposure and prioritize remediation due to the critical severity and potential impact on data confidentiality, integrity, and availability.

Why it matters

CVE-2026-91656 is a critical vulnerability in Oracle Essbase 21.8.3.0.0 that allows a low-privileged attacker with network access via HTTP to compromise the system. This could lead to unauthorized data access, modification, and partial denial of service. Oracle Essbase administrators and security teams should assess exposure and prioritize remediation due to the critical severity and potential impact on data confidentiality, integrity, and availability. The vulnerability's scope change could significantly impact additional products. Remediation priority is high, but specific versions and exploitation details require verification from official sources.

• Potential unauthorized access to critical data.
• Possible unauthorized update, insert or delete access to some Oracle Essbase accessible data.
• Potential partial denial of service (partial DOS) of Oracle Essbase.
• Verification of Oracle Essbase version and patch level is required.

Technical summary

The vulnerability in Oracle Essbase (component: Federated Partitions) is easily exploitable by a low-privileged attacker with network access via HTTP, potentially leading to unauthorized access to critical data, update, insert or delete access to some Oracle Essbase accessible data, and partial denial of service. The CVSS 3.1 Base Score is 9.1, indicating a critical severity level. The vulnerability's scope change could significantly impact additional products, and successful attacks can result in unauthorized access to critical data or complete access to all Oracle Essbase accessible data as well as unauthorized update, insert or delete access to some of Oracle Essbase accessible data and unauthorized ability

Defensive priority

High priority remediation is recommended for Oracle Essbase 21.8.3.0.0 due to the critical severity of this vulnerability.

Recommended defensive actions

• Review and apply Oracle's security patches for Essbase 21.8.3.0.0.
• Restrict network access to Oracle Essbase to only necessary personnel.
• Monitor Oracle Essbase logs for suspicious activity.
• Verify the integrity of Oracle Essbase data and configurations.
• Perform vulnerability scanning to identify exposed systems.
• Implement compensating controls for exposed systems while remediation is scheduled and verified.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE and NVD records provide details on the vulnerability, its impacts, and affected versions. Oracle's advisory is referenced, offering guidance on remediation. The vulnerability is in Federated Partitions component of Oracle Essbase. The CVSS score is 9.1, indicating critical severity. The vector is (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L).

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.