Improper Input Validation in Kibana's Email Connector by Elastic

CVE-2026-0543

What is CVE-2026-0543?

CVE-2026-0543 is a vulnerability found in Kibana's Email Connector developed by Elastic. Kibana is a powerful data visualization and exploration tool used primarily for log and time-series analytics, famously coupled with the Elasticsearch backend. The specific flaw relates to improper input validation within the Email Connector, which is responsible for managing email notifications. This vulnerability can be exploited by an authenticated user with view-level access, who could attack the system by submitting a specially crafted email address. Such an attack can lead to excessive resource allocation, resulting in complete service unavailability until a manual restart of the system is performed. As a result, affected organizations may face disruptions in critical operations that rely on Kibana’s functionalities.

Potential impact of CVE-2026-0543

1. Service Disruption: The immediate consequence of this vulnerability is a denial-of-service scenario, rendering the application inoperable until restarted. This can significantly hinder business operations, particularly in environments that depend on Kibana for real-time data monitoring.

2. System Resource Exhaustion: Exploiting this vulnerability can lead to excessive resource utilization on the server. Over time, this could affect the overall performance of the system and degrade the experience for legitimate users.

3. Authentication Dependency: Since exploitation requires authenticated access, organizations must ensure that users with view-level privileges are managed carefully. If compromised, an attacker could easily disrupt services, posing a security risk to the wider network environment.

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