CVE-2025-68390
📋 TL;DR
This vulnerability allows authenticated Elasticsearch users with snapshot restore privileges to cause memory exhaustion and denial of service through crafted HTTP requests. It affects Elasticsearch deployments where users have snapshot restore permissions. The impact is limited to availability rather than data confidentiality or integrity.
💻 Affected Systems
- Elasticsearch
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of Elasticsearch cluster due to memory exhaustion, affecting all dependent applications and services.
Likely Case
Degraded performance or temporary unavailability of Elasticsearch nodes, requiring manual intervention to restore service.
If Mitigated
Minimal impact if proper access controls limit snapshot restore privileges to trusted administrators only.
🎯 Exploit Status
Requires authenticated user with specific privileges; exploitation involves sending crafted HTTP requests to snapshot restore endpoints.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.19.8, 9.1.8, or 9.2.2
Vendor Advisory: https://discuss.elastic.co/t/elasticsearch-8-19-8-9-1-8-and-9-2-2-security-update-esa-2025-37/384185
Restart Required: Yes
Instructions:
1. Backup your Elasticsearch data and configuration. 2. Download the patched version from elastic.co. 3. Stop Elasticsearch service. 4. Install the new version. 5. Restart Elasticsearch service. 6. Verify cluster health.
🔧 Temporary Workarounds
Restrict Snapshot Restore Privileges
allLimit snapshot restore permissions to only essential administrators to reduce attack surface.
curl -XPUT 'http://localhost:9200/_security/role/restricted_role' -H 'Content-Type: application/json' -d '{"indices": [], "cluster": [], "applications": []}'
curl -XPUT 'http://localhost:9200/_security/user/malicious_user' -H 'Content-Type: application/json' -d '{"password": "newpassword", "roles": ["restricted_role"]}'
🧯 If You Can't Patch
- Implement strict access controls to limit snapshot restore privileges to minimal necessary users.
- Monitor Elasticsearch memory usage and set up alerts for abnormal memory allocation patterns.
🔍 How to Verify
Check if Vulnerable:
Check Elasticsearch version with: curl -XGET 'http://localhost:9200/' and compare against affected versions.Check Version:
curl -XGET 'http://localhost:9200/' | grep numberVerify Fix Applied:
After patching, verify version is 8.19.8, 9.1.8, or 9.2.2+ and test snapshot restore functionality with normal requests.📡 Detection & Monitoring
Log Indicators:
- Unusually large memory allocation in Elasticsearch logs
- Frequent snapshot restore requests from single users
- OutOfMemoryError or similar exceptions
Network Indicators:
- High volume of HTTP POST requests to /_snapshot/*/_restore endpoints
- Abnormal request sizes to snapshot APIs
SIEM Query:
source="elasticsearch.logs" AND ("OutOfMemoryError" OR "memory allocation" OR "_snapshot")