CVE-2026-26935: 
Kibana vulnerability analysis and mitigation

CVE-2026-26935 is an Improper Input Validation vulnerability (CWE-20) in the internal Content Connectors search endpoint of Elastic Kibana that can lead to Denial of Service via Input Data Manipulation (CAPEC-153). It affects Kibana versions 8.4.0 through 8.19.11, 9.0.0 through 9.2.5, and 9.3.0. The vulnerability was published on February 26, 2026, with patches released shortly after. It carries a CVSS v3.1 base score of 7.5 (High) per NVD, though Elastic's own advisory scores it at 6.5 (Medium) with a low-privilege requirement (Elastic Advisory, Red Hat).

The root cause is insufficient input validation (CWE-20) in Kibana's internal Content Connectors search endpoint, which fails to properly sanitize or reject malformed or oversized input data. An attacker can craft and submit manipulated input to this endpoint to trigger a Denial of Service condition, consistent with CAPEC-153 (Input Data Manipulation). According to Elastic's advisory, exploitation requires low privileges (an authenticated user), no user interaction, and is achievable over the network with low attack complexity. No public proof-of-concept code has been identified at this time (Elastic Advisory, Red Hat).

Successful exploitation disrupts the availability of the Kibana service, causing a Denial of Service condition that prevents legitimate users from accessing the platform. There is no impact on confidentiality or data integrity — the vulnerability is limited to availability. Affected deployments include Kibana versions 8.4.0–8.19.11, 9.0.0–9.2.5, and 9.3.0, and any organization relying on Kibana for log analysis, monitoring, or security operations dashboards would experience service disruption (Elastic Advisory).

There is no evidence of active in-the-wild exploitation or a publicly available proof-of-concept exploit as of the time of reporting. The EPSS score is approximately 0.044%, indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires a low-privileged authenticated account, which somewhat limits the attack surface compared to unauthenticated vulnerabilities (Elastic Advisory, Red Hat).

Elastic has released patched versions addressing this vulnerability: 8.19.12 (for the 8.x branch), 9.2.6 (for the 9.0–9.2 branch), and 9.3.1 (for the 9.3 branch). Organizations should prioritize upgrading to these versions. As an interim measure, network access controls should be implemented to restrict access to the Content Connectors search endpoint to only authorized users and systems. Monitoring for unusual request patterns to this endpoint can help detect exploitation attempts (Elastic Advisory).

Elastic published a security advisory (ESA-2026-13) detailing the vulnerability and patched versions. Red Hat tracked the CVE in their security database. Coverage was limited to automated vulnerability aggregators and security tracking platforms, with no notable independent researcher commentary or significant social media discussion identified (Elastic Advisory, Red Hat).