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
Lifecycle Timeline
2DescriptionCVE.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.
AnalysisAI
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.
Technical ContextAI
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.
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.
Kibana versions before 5.6.15 and 6.6.1 contain an arbitrary code execution flaw in the Timelion visualizer. Rated criti
Kibana versions 6.7.0 to 6.8.8 and 7.0.0 to 7.6.2 contain a prototype pollution flaw in the Upgrade Assistant. Rated hig
Kibana versions before 6.4.3 and 5.6.13 contain an arbitrary file inclusion flaw in the Console plugin. Rated critical s
Prototype pollution in Kibana leads to arbitrary code execution via a crafted file upload and specifically crafted HTTP
Kibana versions 4.0 to 4.6, 5.0 to 5.6.12, and 6.0 to 6.4.2 contain an error in the way authorization credentials are us
A Prototype pollution vulnerability in Kibana leads to arbitrary code execution via crafted HTTP requests to machine lea
Kibana versions before 6.6.1 contain an arbitrary code execution flaw in the security audit logger. Rated critical sever
Prototype Pollution in Kibana can lead to code injection via unrestricted file upload combined with path traversal. Rate
Privilege escalation in Elastic Kibana's Agent Builder component (versions 9.4.0-9.4.3) allows authenticated low-privile
A deserialization issue in Kibana can lead to arbitrary code execution when Kibana attempts to parse a YAML document con
Kibana version 8.7.0 contains an arbitrary code execution flaw. Rated high severity (CVSS 8.8), this vulnerability is re
Kibana versions 8.0.0 through 8.7.0 contain an arbitrary code execution flaw. Rated high severity (CVSS 8.8), this vulne
Same technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-58289
GHSA-397q-qwg5-f6mc