CVE-2026-0531
📋 TL;DR
CVE-2026-0531 is a resource exhaustion vulnerability in Kibana Fleet where specially crafted bulk retrieval requests can cause excessive memory consumption leading to server crashes. Attackers with viewer-level privileges can exploit this to cause denial of service. Organizations running vulnerable Kibana versions with Fleet enabled are affected.
💻 Affected Systems
- Kibana Fleet
📦 What is this software?
Kibana by Elastic
Kibana by Elastic
Kibana by Elastic
Kibana by Elastic
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of Kibana Fleet functionality, potentially affecting all users and disrupting monitoring/management capabilities until service restoration.
Likely Case
Temporary service disruption affecting Kibana Fleet operations, requiring server restart and causing monitoring gaps.
If Mitigated
Minimal impact with proper request throttling, monitoring, and quick response to anomalous traffic patterns.
🎯 Exploit Status
Exploitation requires viewer-level authentication but uses simple crafted requests. The vulnerability is publicly documented with technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kibana 8.19.10, 9.1.10, or 9.2.4
Vendor Advisory: https://discuss.elastic.co/t/kibana-8-19-10-9-1-10-9-2-4-security-update-esa-2026-04/384522
Restart Required: Yes
Instructions:
1. Backup Kibana configuration and data. 2. Download and install the patched version from Elastic's official repository. 3. Restart Kibana service. 4. Verify service functionality.
🔧 Temporary Workarounds
Implement request rate limiting
allConfigure reverse proxy or load balancer to limit bulk request frequency and size
# Example nginx configuration:
location /api/fleet/ {
limit_req zone=fleet burst=5 nodelay;
limit_req_status 429;
}
Restrict viewer role access
allTemporarily reduce permissions for viewer roles to exclude Fleet API access
# Kibana role configuration:
# Remove 'read' privilege for 'fleet' feature from viewer roles
🧯 If You Can't Patch
- Implement network segmentation to restrict access to Kibana Fleet endpoints
- Enable detailed monitoring and alerting for abnormal memory consumption patterns
🔍 How to Verify
Check if Vulnerable:
Check Kibana version via API: curl -XGET 'http://localhost:5601/api/status' | grep numberCheck Version:
curl -XGET 'http://localhost:5601/api/status' | grep -o '"number":"[^"]*"'Verify Fix Applied:
Verify version is 8.19.10, 9.1.10, or 9.2.4+ and test bulk retrieval requests with monitoring for memory spikes📡 Detection & Monitoring
Log Indicators:
- Multiple large bulk retrieval requests from single source
- Memory exhaustion warnings in Kibana logs
- Service restart events following memory spikes
Network Indicators:
- High frequency POST requests to /api/fleet/* endpoints
- Abnormally large request payloads to Fleet APIs
SIEM Query:
source="kibana.log" AND ("OutOfMemory" OR "heap memory" OR "GC overhead") AND "fleet"