CVE-2026-91634 in Essbase
Summary
by MITRE • 10/21/2026
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 T3, IIOP to compromise Oracle Essbase. Successful attacks of this vulnerability can result in unauthorized read access to a subset of Oracle Essbase accessible data. CVSS 3.1 Base Score 5.3 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).
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Analysis
by VulDB Data Team • 10/21/2026
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 patch status. This flaw is characterized by its ease of exploitation, allowing an unauthenticated attacker to gain unauthorized access without requiring user interaction or prior authentication credentials. The attack vector leverages the T3 and IIOP protocols, which are standard communication interfaces used for remote method invocation in Java-based enterprise applications like Oracle Essbase. These protocols facilitate data exchange between clients and servers but can be exploited if input validation and access control mechanisms are insufficiently implemented within the service handlers associated with these endpoints.
From a technical perspective, this vulnerability represents an improper authentication or authorization failure where the system fails to adequately verify the identity of users attempting to access sensitive resources through network-facing interfaces. The attacker exploits weaknesses in how Oracle Essbase processes requests sent via T3 and IIOP protocols, bypassing security checks that should restrict access based on user roles or permissions. This misconfiguration allows remote code execution principles to be subverted into information disclosure scenarios where the confidentiality of data is compromised but integrity and availability remain largely unaffected according to current assessments. The flaw aligns with CWE-287 Improper Authentication as it involves failing to properly authenticate users before granting access, and potentially CWE-862 Missing Authorization if specific resource-level permissions are not enforced correctly during request processing.
The operational impact of this vulnerability centers on unauthorized read access to a subset of Oracle Essbase accessible data. While the CVSS 3.1 base score is rated at 5.3 indicating medium severity, primarily due to confidentiality impacts, the consequences can be significant for organizations relying on accurate and secure business intelligence data. Attackers with network access via T3 or IIOP ports can extract sensitive analytical models, financial projections, sales forecasts, or other proprietary datasets stored within Essbase cubes. This exposure violates data privacy regulations such as GDPR or HIPAA if personal information is involved and undermines trust in the integrity of decision-making processes that rely on these analytics platforms. The lack of authentication requirement means any entity with network connectivity to the affected service port can attempt exploitation without detection by traditional perimeter defenses focused solely on blocking unauthorized connections rather than inspecting content for malicious intent.
In terms of threat modeling, this vulnerability maps directly to MITRE ATT&CK technique T1078 Valid Accounts if attackers were able to steal credentials first, but more accurately reflects initial access vectors where unauthenticated entry is possible through protocol-specific flaws. It also relates to data exfiltration techniques as the primary goal involves retrieving information rather than altering or destroying it. Organizations must recognize that even read-only access can lead to further compromise when combined with other vulnerabilities in adjacent systems within the same network segment, enabling lateral movement and deeper infiltration into enterprise infrastructure.
Mitigation strategies should prioritize immediate patching of Oracle Essbase to the latest available version containing security fixes for this specific issue. Administrators are advised to review Oracle Support documentation for relevant patches addressing CVE details related to T3 and IIOP protocol handling in version 21.8.3.0.0. Additionally, network segmentation plays a critical role in reducing exposure by restricting access to Essbase services only from trusted application servers or management networks rather than exposing them directly to general user subnets. Implementing strict firewall rules that limit inbound connections on T3 and IIOP ports to authorized IP addresses can significantly reduce the attack surface. Furthermore, enabling detailed logging for these protocols allows security operations centers to monitor for anomalous access patterns indicative of exploitation attempts. Regular vulnerability scanning focused on middleware components ensures timely detection of similar misconfigurations across the enterprise environment before they can be leveraged by malicious actors seeking unauthorized data retrieval capabilities.