CVE-2026-91639 in Essbase
Summary
by MITRE • 10/22/2026
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 HTTP 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 unauthorized access to critical data or complete access to all Oracle Essbase accessible data. CVSS 3.1 Base Score 7.7 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N).
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Analysis
by VulDB Data Team • 10/22/2026
The identified vulnerability resides within the security component of Oracle Essbase, specifically affecting version 21.8.3.0.0 and potentially other supported releases depending on configuration. This flaw represents a critical weakness in how the application handles authentication and authorization checks for users accessing data through HTTP-based interfaces. The core technical issue involves an insufficient verification mechanism that allows low-privileged attackers to bypass intended access controls when interacting with the service over network connections. Because the vulnerability is located within the security module, it directly undermines the fundamental trust model of the database management system, allowing malicious actors to exploit misconfigured permissions or logic errors in the request processing pipeline to gain unauthorized entry into sensitive data stores.
From an operational perspective, this vulnerability poses a severe risk due to its high ease of exploitation and broad impact scope. An attacker with low privileges who has network access via HTTP can leverage this flaw to compromise Oracle Essbase without requiring user interaction or complex preconditions. The consequences are particularly alarming because the attack may significantly impact additional products beyond just Essbase, indicating a potential for lateral movement or cross-product privilege escalation within an integrated enterprise environment. This scope change amplifies the risk profile, as it suggests that compromising this single entry point could lead to broader system instability or data exposure across multiple organizational assets dependent on Oracle infrastructure.
The primary outcome of a successful exploitation is unauthorized access to critical business intelligence data and potentially complete access to all accessible information within the Essbase environment. This results in a high impact on confidentiality, as classified by the CVSS 3.1 base score of 7.7. The vector string AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N highlights that while integrity and availability remain unaffected according to this specific assessment, the loss of data secrecy is severe. Attackers can extract sensitive financial models, sales forecasts, or strategic planning documents without detection if logging mechanisms are not robustly configured. This aligns with CWE-287 Improper Authentication and CWE-269 Improper Privilege Management, as the flaw allows a lower-level entity to perform actions reserved for higher-privileged roles or access resources outside their designated scope.
To mitigate this vulnerability, organizations must immediately apply the latest security patches provided by Oracle for Essbase version 21.8.3.0.0 and subsequent updates that address these specific authentication flaws. In addition to patching, it is critical to enforce strict network segmentation policies to limit HTTP access to only authorized management interfaces or internal subnets where possible. Implementing Web Application Firewalls with rules specifically tuned for Oracle Essbase traffic patterns can help detect and block exploitation attempts before they reach the application layer. Furthermore, administrators should review user roles and permissions regularly to ensure that low-privileged accounts do not possess unnecessary access rights to critical data sets, thereby reducing the blast radius if a breach occurs. Monitoring logs for anomalous authentication behaviors consistent with ATT&CK technique T1078 Valid Accounts can also aid in early detection of such exploitation activities.