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Oracle Essbase EUVDEUVD-2026-106842

| CVE-2026-91655 CRITICAL
Improper Access Control (CWE-284)
2026-10-20 secalert_us@oracle.com GHSA-6mw7-mcpr-3q6v
9.1
CVSS 3.1 · Vendor: oracle
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privileged Essbase credentials
  2. Delivery
    Send crafted HTTP request to Security component
  3. Exploit
    Exploit flaw crossing scope boundary
  4. Execution
    Access critical data in additional products
  5. Impact
    Exfiltrate data and cause partial DoS

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the attacker to already possess low-privileged authenticated access to Oracle Essbase 21.8.3.0.0 and network reachability to its HTTP interface (AV:N, PR:L, AC:L, UI:N). The flaw resides specifically in the Essbase Security component. The key amplifying condition is the scope change (S:C): a successful attack can reach beyond Essbase itself to significantly impact additional connected products, broadening the blast radius. The principal limiting factors are the credential requirement (not remotely exploitable by a fully unauthenticated attacker) and the restriction to the specific affected version 21.8.3.0.0; no special non-default configuration or user interaction is indicated as necessary.

Impact

This is a genuinely high-priority issue despite several intelligence gaps. The CVSS 3.1 base score of 9.1 is driven primarily by the scope change (S:C) combined with network exploitability (AV:N), low attack complexity (AC:L), no user interaction (UI:N), and high confidentiality impact (C:H), with lower integrity and availability impact (I:L/A:L). Crucially, the vector specifies PR:L, meaning exploitation requires some level of authentication - the attacker must already hold low-privileged credentials, which is a meaningful mitigating factor against purely opportunistic internet-wide exploitation. No EPSS probability was provided, the CVE is NOT on the CISA KEV list, and no public POC is referenced, so there is no evidence of active exploitation or weaponization at this time; the elevated score reflects potential impact, not observed attack activity. There is also a notable conflict in the metadata: the input carries an 'Authentication Bypass' tag, yet both the description ('low privileged attacker') and the CVSS vector (PR:L) indicate that valid credentials are required - this is inconsistent and should be verified against Oracle's CPU advisory, as a true authentication bypass would warrant PR:N and a different risk profile. Treat this as a high-severity, credentialed, network-reachable flaw with cross-product (scope-change) blast radius: prioritize patching, but recognize the authentication precondition tempers real-world mass-exploitation risk relative to the raw 9.1 score.

Exploit ScenarioDerived

An attacker who has obtained low-privileged Essbase credentials (e.g., a standard application account, or credentials from phishing or reuse) sends crafted HTTP requests to the Essbase Security component over the network. Because of the scope change, the attacker is able to read critical data across the Essbase instance and partially modify or disrupt data in additional connected products. No public exploit code has been identified at the time of analysis, so this scenario is inferred from the CVSS vector rather than a demonstrated POC.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 20, 2026

Authenticated low-privileged attackers with HTTP network access to Oracle Essbase 21.8.3.0.0 can exploit a flaw in the Security component to read critical Essbase-accessible data, make limited unauthorized updates, inserts, or deletions, and cause a partial denial of service. The CVSS 3.1 score is 9.1 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L), with the scope change indicating that successful exploitation can significantly affect additional connected products beyond Essbase. No public exploit identified at time of analysis; exploitation requires valid low-privileged credentials and reachability to the HTTP interface.

RemediationAI

Primary remediation is to apply the Oracle Essbase security fix listed in the October 2026 Critical Patch Update (https://www.oracle.com/security-alerts/cpuoct2026.html); the supplied data does not give an exact patched version, so confirm the fixed 21.8.3.x build with Oracle and upgrade from 21.8.3.0.0. Until patched, restrict HTTP access to Essbase to trusted networks and required integration hosts, which reduces exposure but may break legitimate connected-product integrations; review and reduce Essbase user privileges to the minimum needed, accepting possible disruption to business roles; and segment Essbase from additional connected products while monitoring for anomalous cross-product access, which limits the scope-change blast radius but adds network complexity. No vendor workaround is supplied in the references, so these compensating controls should be treated as temporary.

Affected VersionsENISA

Oracle Essbase 21.8.3.0.0

Affected Packages

euvd oracle_essbase no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Oracle Essbase is an OLAP/analytics server, and the affected Security component mediates access to cubes and data. The vulnerability is reachable over HTTP with low attack complexity, requires low privileges (PR:L), and needs no user interaction. The CVSS 3.1 score of 9.1 reflects high confidentiality, low integrity, and low availability impact plus a scope change (S:C), meaning a successful exploit can read critical Essbase-accessible data, make limited unauthorized modifications, and partially disrupt availability while also significantly affecting additional products outside Essbase's security scope. No CWE is assigned in the input; the Security-component location and impact profile point to an access-control/authorization weakness, but the precise root cause is not publicly classified. A supplied tag mentions Authentication Bypass, yet the authoritative assessment requires an existing low-privileged account, so this must not be treated as unauthenticated access.

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Severity by source

Vendor (oracle) PRIMARY 9.1 CRITICAL
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
vuln.today AI 9.1 CRITICAL

Network HTTP vector with low complexity and no user interaction, but PR:L because low-privileged credentials are required; scope change and high confidentiality with partial integrity/availability impact per Oracle's description.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:L/SC:H/SI:L/SA:L

Primary rating from Vendor (oracle).

CVSS VectorVendor: oracle

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
Low

DescriptionCVE.org

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 as well as unauthorized update, insert or delete access to some of Oracle Essbase accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Essbase. CVSS 3.1 Base Score 9.1 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L).

Executive ViewAI

Why It Matters

Oracle Essbase 21.8.3.0.0 contains a critical Security component flaw that lets authenticated low-privileged users with HTTP access read critical Essbase data, make limited unauthorized changes, and cause partial service disruption, with potential scope expansion into connected products. Because no public exploit has been identified at time of analysis and no vendor-released patch is available, leadership should treat this as a high-priority exposure requiring access restriction and monitoring, especially where low-privilege accounts are broadly provisioned.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis; restrict HTTP access to Essbase 21.8.3.0.0, enforce least privilege and disable unnecessary low-privileged accounts, segment the service from general networks and connected products, enable audit logging and alerting on unauthorized reads/writes and availability events, and maintain validated backups.

Threat Intelligence Overview

EPSS Score
0.2%
Top 90% exploitable
Prevalence
Medium
enterprise OLAP/BI analytics server, moderate corporate footprint, not ubiquitous
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact
High

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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