Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to Kibana as low-privilege user
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DeliveryEnumerate or infer ML model deployment IDs in other Spaces
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ExploitCraft cross-space API request with user-controlled deployment key
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ExecutionBypass Space ACL via CWE-639 authorization failure
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PersistExtract inference outputs exposing model behavior
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ImpactOptionally stop or reconfigure model deployment in target Space
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Object-level authorization, IDOR prevention
|
| Exploitation Conditions | The attacker must hold a valid, authenticated Kibana account (PR:L in the CVSS vector confirms this). The target environment must be running Kibana with the Elastic ML feature active (Stack ML, requiring at minimum a Platinum license or Elastic Cloud subscription tier that enables trained model deployments). Multiple Kibana Spaces must be in use - single-Space deployments are not meaningfully exposed because there is no cross-space boundary to bypass. The attacker must know or be able to guess/enumerate a valid model deployment ID or inference endpoint identifier belonging to the target Space; the CPE wildcard indicates no version-specific prerequisite. Exploitation is limited to users who already have network access to the Kibana API (no external unauthenticated path exists given PR:L). Users without a Kibana account and environments not using Kibana's ML model deployment feature are not at risk. |
| Impact | The CVSS base score of 7.1 (High) is driven primarily by C:H (full disclosure of cross-space model inference outputs) and A:L (ability to stop active deployments). The official vector records I:N, though the deployment-update operation - allowing arbitrary resource reallocation - arguably warrants I:L, yielding a score closer to 7.6. PR:L confirms a valid Kibana account is required, which substantially limits the attacker population to existing authenticated users rather than anonymous internet actors. AC:L indicates no special configuration or timing is needed once authentication is obtained. No EPSS data was provided; without it, base-rate exploitation probability cannot be quantified. The vulnerability is not listed in CISA KEV and no POC has been identified, indicating no confirmed active exploitation at time of analysis. Real-world priority is highest for multi-tenant Kibana deployments using the Elastic ML feature (Stack ML or Platinum/Enterprise subscription tiers), where cross-tenant confidentiality of model behavior is a business concern. Organizations running Kibana in single-Space or non-ML configurations face no material risk from this specific flaw. |
| Exploit ScenarioDerived | An authenticated Kibana user assigned to Space A crafts API requests referencing trained ML model deployment IDs or inference endpoint paths belonging to Space B - IDs that the attacker has discovered through enumeration, leaked logs, or prior access. Because the authorization check does not validate Space membership of the resolved resource, the API returns inference outputs that reveal model behavior (e.g., classification logic, embedding patterns) from Space B. The same attacker can issue deployment-stop or resource-update requests against the Space B model, disrupting production ML inference for another team or tenant without ever appearing in Space B's audit logs. No public POC has been identified, so this scenario currently requires manual exploitation by a knowledgeable attacker. |
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Alert meAnalysisAIv1 – Aug 13, 2026
Cross-space authorization bypass in Kibana allows authenticated users to access trained machine learning model inference outputs, and stop or modify active model deployments, in Kibana Spaces they are not authorized to access. The vulnerability arises because API endpoints for ML model inference and deployment management accept user-controlled resource identifiers without enforcing space-level ACL boundaries, enabling privilege escalation across the Space isolation boundary. No public exploit code has been identified and Elastic has released fixed versions 8.19.20, 9.4.5, and 9.5.1 per advisory ESA-2026-126.
RemediationAI
The primary fix is to upgrade Kibana to version 8.19.20, 9.4.5, or 9.5.1 as documented in Elastic security advisory ESA-2026-126 (https://discuss.elastic.co/t/kibana-8-19-20-9-4-5-9-5-1-security-update-esa-2026-126/389530). For organizations unable to patch immediately, a compensating control is to restrict access to Kibana's trained model inference and deployment management API endpoints (typically under /api/ml/ and /_ml/ paths) at the reverse-proxy or network layer to only users and services that legitimately require ML model access. The trade-off is that this may disrupt legitimate ML workflows if access lists are not carefully scoped. Additionally, auditing Kibana Space membership to ensure only trusted, vetted users hold any authenticated access reduces the attacker pool. Note that disabling the Elastic ML feature entirely (if not in use) eliminates exposure to this specific vulnerability path without impacting core observability functionality.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
Kibana's Spaces feature provides logical tenant isolation, allowing organizations to partition dashboards, ML models, and other resources so that users in one Space cannot access resources in another. The vulnerable code paths govern ML trained model inference (read operations) and deployment management (stop and resource-allocation update operations). CWE-639 (Authorization Bypass Through User-Controlled Key) identifies the root cause: the application uses a caller-supplied model or deployment identifier as a lookup key but fails to validate that the resolved resource resides within a Space the caller is authorized to access, matching CAPEC-1 (Accessing Functionality Not Properly Constrained by ACLs). The affected CPE is cpe:2.3:a:elastic:kibana:*:*:*:*:*:*:*:*, covering all versions prior to the patched releases. The CVSS vector AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L reflects a network-reachable API requiring only low-privilege Kibana authentication.
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L
PR:L confirmed by vendor CVSS; I:L added over official score because deployment resource modification constitutes an integrity impact not captured by I:N.
Primary rating from Vendor (elastic).
CVSS VectorVendor: elastic
DescriptionCVE.org
Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana can lead to unauthorized cross-space access via Accessing Functionality Not Properly Constrained by ACLs (CAPEC-1). The result is disclosure of inference output from a trained model in a different space that the user is not authorized to list, read, or use, which exposes the behavior of a model. The same pattern also reached the deployment stop and deployment update operations, allowing an active trained model deployment in another space to be stopped or to have its allocated resources altered.
Executive ViewAI
Kibana contains a cross-space authorization bypass allowing authenticated users to access machine learning model outputs and modify deployments across unauthorized spaces, creating data exposure and service disruption risks for organizations using Kibana's space-based access controls for multi-tenant security.
Apply vendor patch.
Threat Intelligence Overview
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
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EUVD-2026-58289
GHSA-397q-qwg5-f6mc
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB