Elasticsearch Memory Exhaustion via Unvalidated Size Parameter
CVE-2026-72678 Published on August 13, 2026
Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service
Elasticsearch does not validate a size value taken from a user-supplied input before that value is used to reserve memory for an internal data structure. An authenticated user holding only read privileges can submit a single small crafted request to a product API endpoint that causes the node to attempt an excessively large allocation. The resulting memory exhaustion raises a fatal error that terminates the Elasticsearch node process, causing a denial of service for the affected node and degrading cluster health. The defect is not volumetric, so a single request is sufficient regardless of the heap size configured on the target node.
Vulnerability Analysis
CVE-2026-72678 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2026-72678 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-72678
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Affected Versions
Elasticsearch:- Version 8.19.0, <= 8.19.19 is affected.
- Version 9.4.0, <= 9.4.4 is affected.
- Version 9.5.0 is affected.