CVE-2026-56147 Overview
CVE-2026-56147 is an authorization bypass vulnerability in Kibana tracked under CWE-639, Authorization Bypass Through User-Controlled Key. The flaw stems from inconsistent resolution logic between Kibana's file access authorization check and its resource retrieval path. A low-privileged authenticated user with limited file management permissions can retrieve, modify, and delete case attachments belonging to feature areas they do not own. Attachments tied to Security Solution cases are directly exposed. Elastic disclosed the issue in the Kibana 8.19.18, 9.3.7, and 9.4.3 Security Update Advisory.
Critical Impact
Authenticated attackers with minimal privileges can read, alter, and delete Security Solution case attachments, exposing investigative artifacts and compromising case integrity.
Affected Products
- Kibana versions prior to 8.19.18
- Kibana 9.x versions prior to 9.3.7
- Kibana 9.4.x versions prior to 9.4.3
Discovery Timeline
- 2026-07-21 - CVE-2026-56147 published to NVD
- 2026-07-22 - Last updated in NVD database
Technical Details for CVE-2026-56147
Vulnerability Analysis
Kibana exposes a case management feature where users can attach files to cases scoped to specific feature areas, including the Security Solution. Access to attachments is governed by feature-based authorization tied to the owning application. CVE-2026-56147 breaks this model because the file authorization check and the file retrieval routine resolve the target resource using different mechanisms. An attacker holding only generic file management permissions can therefore reference an attachment identifier that belongs to a feature area they cannot access. The authorization layer approves the request while the retrieval layer serves the protected object.
The impact covers confidentiality and integrity. The attacker can read attachment contents, replace them with attacker-controlled data, or delete them entirely. Case attachments frequently contain forensic exports, screenshots, malware samples, and analyst notes tied to active investigations.
Root Cause
The root cause is a mismatch in identifier resolution between the authorization check and the storage lookup. The authorization layer treats the supplied key as belonging to the caller's feature scope, while the retrieval layer resolves the same key against a global attachment store. This is a classic Insecure Direct Object Reference pattern under CWE-639, aligned with CAPEC-122 Privilege Abuse.
Attack Vector
Exploitation requires network access to Kibana and a valid low-privileged account with file management permissions. The attacker enumerates or guesses attachment identifiers and issues HTTP requests to the case attachment endpoints. No user interaction is required. Successful requests return, mutate, or remove attachments tied to Security Solution or other privileged feature areas without triggering an authorization failure. See the Elastic Security Update Advisory for vendor-provided details.
Detection Methods for CVE-2026-56147
Indicators of Compromise
- Kibana audit log entries showing successful GET, PUT, or DELETE operations on case attachment endpoints by users lacking Security Solution privileges.
- Unexpected modifications or deletions of case attachments tied to Security Solution cases.
- Requests to /api/cases/*/attachments/* or internal file endpoints originating from accounts that do not own the referenced case.
Detection Strategies
- Correlate Kibana access logs with user role assignments to identify cross-feature attachment access.
- Alert when a single low-privileged account accesses attachment identifiers spanning multiple feature owners in a short window.
- Compare hashes of stored attachments against known-good baselines to identify silent tampering.
Monitoring Recommendations
- Forward Kibana audit logs to a centralized SIEM or data lake and normalize case and attachment fields.
- Track authentication events for accounts holding file management permissions and review activity against case scopes.
- Monitor attachment deletion volumes and flag deviations from baseline analyst behavior.
How to Mitigate CVE-2026-56147
Immediate Actions Required
- Upgrade Kibana to version 8.19.18, 9.3.7, or 9.4.3 depending on your deployment branch.
- Audit user roles and revoke file management permissions from accounts that do not require them.
- Review case attachment access history for the period preceding the upgrade to identify potential abuse.
Patch Information
Elastic addressed CVE-2026-56147 in Kibana 8.19.18, 9.3.7, and 9.4.3. Details are published in the Kibana Security Update Advisory ESA-2026-59. Apply the update through your standard Elastic Stack upgrade process and validate that all Kibana nodes report the patched build.
Workarounds
- Restrict Kibana access to trusted networks using a reverse proxy or firewall until patches are applied.
- Remove or downgrade roles that grant file management privileges to users outside the case management workflow.
- Where feasible, disable the case attachment feature for non-privileged Kibana spaces until upgrades complete.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
