CVE-2026-33458: 
Kibana vulnerability analysis and mitigation

CVE-2026-33458 is a Server-Side Request Forgery (SSRF) vulnerability in the Kibana One Workflow feature (Workflows Execution Engine) that can lead to information disclosure. An authenticated user with workflow creation and execution privileges can bypass host allowlist restrictions, potentially exposing sensitive internal endpoints and data. The vulnerability affects Kibana versions 9.3.0 through 9.3.2 (fixed in 9.3.3), and was published on April 8, 2026. It carries a CVSS v3.1 base score of 7.7 (High) per Feedly/NVD, though the GitHub Advisory Database rates it 6.3 (Moderate) (GitHub Advisory, Elastic Advisory).

The vulnerability is classified as CWE-918 (Server-Side Request Forgery) and resides in the Kibana Workflows Execution Engine, which is part of the "One Workflow" feature. The root cause is insufficient enforcement of host allowlist restrictions, allowing an authenticated attacker to craft workflow definitions that cause the Execution Engine to make HTTP requests to arbitrary internal hosts or endpoints not permitted by the configured allowlist. Exploitation requires network access to Kibana and a low-privilege authenticated account with workflow creation and execution rights; no user interaction is needed and the scope change (S:C) indicates the impact extends beyond the Kibana component itself to internal backend systems (GitHub Advisory, Elastic Advisory).

Successful exploitation allows an authenticated attacker to make the Kibana Workflows Execution Engine issue HTTP requests to internal hosts and endpoints that should be inaccessible, effectively using Kibana as a proxy to probe or retrieve data from internal services, databases, or APIs. The confidentiality impact is rated High with no integrity or availability impact, meaning the primary risk is unauthorized disclosure of sensitive internal data. This could expose backend service responses, internal API data, cloud metadata endpoints (e.g., AWS IMDSv1), or other restricted resources reachable from the Kibana server's network position (GitHub Advisory, Elastic Advisory).

As of the time of disclosure, there is no public proof-of-concept exploit and no evidence of in-the-wild exploitation. The EPSS score is approximately 0.042–0.048%, placing it in the 15th percentile for exploitation likelihood within 30 days. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires authenticated access with specific workflow privileges, which limits the attack surface compared to unauthenticated vulnerabilities (GitHub Advisory).

1. Reconnaissance: Identify a Kibana instance running version 9.3.0–9.3.2 with the One Workflow feature enabled. Confirm the attacker has or can obtain a low-privilege account with workflow creation and execution permissions.
2. Craft malicious workflow: Create a new workflow definition that includes an HTTP request action targeting an internal host or endpoint not permitted by the configured allowlist (e.g., http://169.254.169.254/latest/meta-data/ for cloud metadata, or internal service addresses like http://internal-db:9200/).
3. Bypass allowlist: Submit the crafted workflow through the Kibana UI or API. The Workflows Execution Engine fails to properly enforce the host allowlist, allowing the request to proceed to the restricted destination.
4. Retrieve response: The Execution Engine fetches the response from the internal endpoint and returns it within the workflow execution result, which the attacker can read via the Kibana interface or API response.
5. Exfiltrate data: Use the retrieved internal data (credentials, tokens, service configurations, or sensitive API responses) for further lateral movement or privilege escalation within the internal network (GitHub Advisory, Elastic Advisory).

• Logs: Kibana workflow execution logs showing HTTP requests to unexpected internal IP ranges (RFC 1918 addresses), cloud metadata endpoints (e.g., 169.254.169.254), or hosts not in the configured allowlist.
• Network: Outbound HTTP/HTTPS connections from the Kibana server process to internal services (e.g., Elasticsearch nodes on non-standard ports, internal APIs, database management interfaces) initiated by workflow execution.
• Logs: Repeated workflow creation and execution events by a single low-privilege user account, particularly with short intervals or automated patterns.
• Logs: Kibana audit logs showing workflow API calls (POST /api/workflows) with payload bodies referencing internal hostnames or IP addresses.

Elastic has released Kibana 9.3.3 as the patched version, and upgrading to this release is the recommended remediation (Elastic Advisory). As interim workarounds, administrators should restrict workflow creation and execution privileges to only trusted users, implement network-level egress controls to limit outbound connections from the Kibana server to approved internal hosts, and monitor workflow execution logs for requests targeting unexpected internal endpoints. Additional authentication or authorization checks for sensitive workflow operations should also be considered where feasible.