Elasticsearch OOM via Forged Opaque ID allows DoS
CVE-2026-72687 Published on August 13, 2026
Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service
A flaw in Elasticsearch allows a low-privileged authenticated user to submit a single small request containing a forged opaque identifier. Elasticsearch decodes and deserializes the identifier before confirming that it was legitimately issued by the cluster, and a size value carried inside the identifier drives an allocation that is neither capped nor accounted for by the available memory-usage controls. The resulting out-of-memory condition is fatal and terminates the affected node process, resulting in a denial of service.
Vulnerability Analysis
CVE-2026-72687 can be exploited 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-2026-72687 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-72687
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Affected Versions
Elasticsearch:- Version 8.0.0, <= 8.19.19 is affected.
- Version 9.0.0, <= 9.4.4 is affected.
- Version 9.5.0 is affected.