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The vulnerability resides in the snapshot restore functionality of Elasticsearch. An authenticated user with the specific privilege to restore snapshots can send a specially crafted HTTP request to the restore API endpoint. This malicious request is designed to trigger an excessive allocation of Java heap memory during the deserialization and processing of snapshot metadata. The attack exploits a lack of proper limits or throttling on resource consumption during this operation. By submitting a request with carefully constructed metadata that defines an abnormally large number of indices, shards, or complex data structures, the attacker can cause the Elasticsearch node to allocate memory far beyond normal operational limits. This uncontrolled memory consumption leads to a sustained high memory pressure on the JVM, eventually triggering OutOfMemoryError conditions. When this occurs, the affected Elasticsearch node will become unresponsive or crash, resulting in a denial of service (DoS) for all users and potentially disrupting the entire cluster if critical master nodes are targeted. The attack leverages the inherent trust in the authenticated snapshot restore process to exhaust system resources.
Platform: Elasticsearch
Version: < 8.19.8
Vulnerability: Excessive Resource Allocation
Severity: Moderate
Date: Dec 19 2025
Prediction: Patch Date: Jan 15 2026
What Undercode Say:
curl -X POST
snapshot.restore.indices: “”
“max_restore_bytes_per_sec”: “0”
java.lang.OutOfMemoryError
Heap usage monitoring
JVM pressure alert
How Exploit:
Crafted restore API request.
Abusive metadata deserialization.
Triggers memory exhaustion.
Protection from this CVE
Apply patched versions.
Restrict snapshot privileges.
Monitor heap usage.
Impact:
Denial of Service.
Cluster instability.
Memory exhaustion crash.
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Sources:
Reported By: github.com
Extra Source Hub:
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