CVE-2026-91637 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 takeover of Oracle Essbase. CVSS 3.1 Base Score 9.9 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).
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Analysis
by VulDB Data Team • 10/22/2026
The identified vulnerability resides within the security component of Oracle Essbase version 21.8.3.0.0, representing a critical flaw that fundamentally undermines the integrity and confidentiality of the application environment. This specific weakness is characterized by its high exploitability, requiring only low-privileged access with network connectivity via HTTP to trigger the malicious conditions necessary for compromise. The severity of this issue is underscored by a CVSS 3.1 Base Score of 9.9, indicating that it poses an extreme threat to organizational security postures. The vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) reveals several critical attributes: the attack is network-based with low complexity and requires no user interaction, yet it demands only local or low-level privileges initially. Crucially, the scope change indicator signifies that while the vulnerability originates in Oracle Essbase, its exploitation allows an attacker to pivot into other connected products or systems within the enterprise ecosystem, thereby expanding the blast radius of a single successful exploit beyond the immediate application boundary.
From a technical perspective, this flaw likely involves improper access control mechanisms or insufficient validation of security contexts during HTTP-based interactions with the Essbase service. The ability for a low-privileged attacker to achieve full takeover suggests that authentication checks may be bypassed or that privilege escalation paths are exposed through poorly secured endpoints. This aligns closely with CWE categories such as Improper Privilege Management (CWE-269) and Broken Access Control (CWE-284), where the system fails to enforce intended restrictions on authenticated users. Furthermore, because the attack vector is network-accessible via HTTP without user interaction, it maps directly to ATT&CK techniques involving Initial Access through valid accounts or exploiting service vulnerabilities, specifically those that allow for lateral movement and privilege escalation within a compromised environment. The high impact on confidentiality, integrity, and availability means that an attacker can not only read sensitive data but also modify configurations or disrupt services entirely, leading to significant operational downtime and potential regulatory non-compliance depending on the nature of the stored data.
The operational impact of this vulnerability is severe due to its ease of exploitation and broad scope change implications. Once an attacker gains initial foothold through low-privileged credentials, they can escalate privileges to gain administrative control over Oracle Essbase. This level of access typically grants the ability to manipulate multidimensional analytical databases, alter business intelligence reports, and potentially inject malicious code or exfiltrate proprietary financial data. The impact extends beyond Essbase itself; because attacks may significantly impact additional products, this vulnerability serves as a potential entry point for broader enterprise compromise. Attackers could leverage the compromised Essbase instance to access linked Oracle databases, middleware components, or other integrated systems that trust the Essbase environment implicitly. This creates a chain reaction of security failures where one weak link in the authentication and authorization architecture leads to systemic collapse across multiple dependent services.
Mitigation strategies must prioritize immediate remediation given the high severity score and ease of exploitation. The primary defense is applying the latest vendor-provided patches or updates that address this specific flaw within Oracle Essbase version 21.8.3.0.0. Organizations should verify their deployment versions against official security advisories to ensure they are not running vulnerable builds. In addition to patching, implementing strict network segmentation can help contain potential lateral movement if the vulnerability is exploited before patches are applied. Restricting HTTP access to only trusted internal networks and enforcing HTTPS with strong certificate validation reduces the attack surface for remote exploitation. Furthermore, auditing existing user privileges within Essbase ensures that no unnecessary low-privileged accounts have broad permissions that could be leveraged for escalation. Regular security assessments and penetration testing focused on authentication bypasses and privilege escalation paths are recommended to identify similar weaknesses in related products before they can be exploited by malicious actors seeking to expand their access across the enterprise infrastructure.