CVE-2026-91659 in Essbase
Summary
by MITRE • 10/22/2026
Vulnerability in Oracle Essbase (component: Build). 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 Build component of Oracle Essbase, specifically affecting version 21.8.3.0.0 and potentially other supported releases depending on their configuration and integration with broader enterprise architectures. This flaw represents a critical security deficiency that allows for unauthorized access to sensitive information stored within the data warehouse environment managed by Essbase. The nature of this vulnerability is characterized by its ease of exploitation, requiring only low-privileged credentials and network connectivity via HTTP to initiate an attack vector against the affected system.
From a technical perspective, the flaw likely stems from insufficient input validation or improper access control mechanisms within the build process logic that handles data ingestion or metadata management. An attacker leveraging this weakness can bypass standard authentication barriers due to the low privilege requirement, exploiting the trust relationship inherent in HTTP-based interactions with the Essbase server. The vulnerability enables the extraction of critical business intelligence data, financial models, and analytical datasets that are central to organizational decision-making processes. Because Oracle products often share underlying infrastructure or database schemas, a compromise in Essbase can lead to scope changes where additional connected applications become vulnerable, amplifying the blast radius beyond the immediate application layer.
The operational impact of this vulnerability is severe, primarily driven by high confidentiality impacts as indicated by the CVSS 3.1 base score of 7.7. Successful exploitation results in unauthorized access to critical data or complete access to all Oracle Essbase accessible data. This level of compromise can lead to significant business disruption, regulatory non-compliance due to exposure of personally identifiable information or financial records, and potential competitive disadvantage through the theft of proprietary analytical models. The attack vector is classified as network-accessible with low complexity, meaning that remote attackers do not require user interaction or complex setup procedures to exploit this flaw once they have valid but low-level credentials on the network segment hosting the Essbase instance.
In terms of industry standards classification, this vulnerability aligns with CWE-200, which covers Exposure of Sensitive Information to an Unauthorized Actor, and potentially CWE-862 if it involves missing authorization checks for specific data resources. From a tactical standpoint within the MITRE ATT&CK framework, this behavior corresponds to techniques such as T1530 Data from Local System Extraction or T1074 Data Staged, depending on how the attacker exfiltrates the accessed data. The scope change aspect highlights the risk of lateral movement and cascading failures in integrated Oracle environments where Essbase serves as a key component of the business intelligence stack.
Mitigation strategies must prioritize immediate patching to the latest available version of Oracle Essbase that addresses this specific build-related flaw, following Oracle Critical Patch Update guidelines. Organizations should also implement strict network segmentation to limit HTTP access to only authorized management interfaces and enforce multi-factor authentication for all administrative accounts to mitigate the risk posed by low-privileged credential theft. Additionally, deploying web application firewalls with rulesets tuned to detect anomalous data retrieval patterns can provide an additional layer of defense against exploitation attempts while patching efforts are underway. Continuous monitoring of Essbase logs for unusual access patterns or large-scale data queries is essential for early detection and response to potential compromise events.