CVE-2026-91661 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 security deficiency that allows for unauthorized access to sensitive data stored within the enterprise analytics platform. The nature of this weakness is characterized by its ease of exploitation, requiring only low-privileged credentials from an attacker who has network connectivity via HTTP to the affected system. Unlike complex vulnerabilities that demand high privilege levels or user interaction, this issue can be leveraged by attackers with minimal access rights, significantly lowering the barrier for entry in environments where basic user accounts are provisioned without strict segmentation.
From a technical perspective, the vulnerability enables an attacker to bypass intended security controls and retrieve critical data that should remain restricted. The impact is primarily focused on confidentiality, as indicated by the high severity score driven entirely by unauthorized access capabilities rather than integrity or availability disruptions. Successful exploitation results in the exposure of sensitive business intelligence data, financial records, or strategic analytics housed within Essbase cubes. This level of data exfiltration can lead to significant competitive disadvantage, regulatory non-compliance, and reputational damage for organizations relying on Oracle Essbase for decision-making processes. The ability to access all accessible data implies a complete compromise of the confidentiality layer of the CIA triad for this specific application domain.
The operational impact extends beyond the immediate scope of Oracle Essbase due to potential scope changes in attack chains. In many enterprise architectures, authentication systems and data stores are interconnected through single sign-on mechanisms or shared database backends. Consequently, compromising an account with low privileges in Essbase may serve as a foothold for lateral movement within the network. Attackers can use this initial access to pivot toward more critical assets, such as core databases, application servers, or other integrated systems that trust the compromised identity. This amplification effect transforms what might appear as a localized data leak into a broader infrastructure compromise, potentially leading to complete control over interconnected services and further escalation of privileges through subsequent exploitation steps.
In terms of industry standard classifications, this vulnerability aligns with CWE-284 Improper Access Control or CWE-798 Use of Hardcoded Credentials if the flaw involves default configurations, though it most closely resembles weaknesses related to insufficient authorization checks in web applications. The attack vector corresponds to MITRE ATT&CK techniques involving Initial Access through valid accounts and potentially Credential Dumping if session tokens are intercepted. Given that the exploitation requires network access via HTTP rather than HTTPS, there is also an implication of Cleartext Transmission of Sensitive Information (CWE-319) or insufficient encryption in transit, which facilitates man-in-the-middle attacks to capture credentials before they even reach the application logic for validation flaws.
Mitigation strategies must prioritize immediate patching and access control hardening. Organizations should apply the latest security patches provided by Oracle for Essbase version 21.8.3.0.0 as soon as feasible, ensuring that all related components are updated to address the underlying code defects. Simultaneously, it is critical to enforce strict network segmentation to limit HTTP-based access from untrusted networks. Implementing Web Application Firewalls can help detect and block exploitation attempts by filtering malicious requests before they reach the application layer. Additionally, enforcing multi-factor authentication for all user accounts reduces the risk of credential compromise being leveraged against this vulnerability. Regular audits of user permissions should be conducted to ensure that low-privileged users do not possess excessive data access rights, adhering to the principle of least privilege to minimize the blast radius in case of a successful breach.