CVE-2026-72639 Memory Allocation with Excessive Size Value in Elasticsearch Highlighting Leading to Denial of Service
An authenticated user can cause a denial of service in Elasticsearch by submitting a search request with an excessive highlighting count, leading to memory exhaustion and node termination.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72639?
CVE-2026-72639 is a medium-severity denial of service vulnerability in Elastic Elasticsearch, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Elasticsearch does not enforce an upper bound on a user-supplied count accepted by a search highlighting option, and the allocation derived from that count is not accounted against any circuit breaker. An authenticated user holding only read privileges on a single searchable index can submit one small search request that causes the node to reserve an excessively large internal data structure. The allocation occurs before the existing highlighting safety limits are evaluated, so memory exhaustion raises a fatal error that terminates the Elasticsearch node process. This results in a denial of service for the affected node and degrades cluster routing and health. The defect is not volumetric and does not depend on the size of the indexed data, so a single request is sufficient.
Weakness: CWE-789
Which versions are affected by CVE-2026-72639?
1 open source package ship an affected version, including elasticsearch. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
elasticsearch Bitnami | From 8.19.0 | 8.19.20, 9.5.1 |
Products include Elastic Elasticsearch.
How do I fix CVE-2026-72639?
Upgrade elasticsearch to a fixed version for your release line: 8.19.20 or 9.5.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-72639 being exploited?
There is no known exploitation of CVE-2026-72639 in the wild and no public exploit code.
Other vulnerabilities in Elastic Elasticsearch
- CVE-2015-1427 Elasticsearch Groovy Scripting Engine Remote Code Execution
- CVE-2014-3120 Elasticsearch Remote Code Execution
- CVE-2015-5377 Code injection in n/a
- CVE-2026-72649 Deserialization of Untrusted Data in Elasticsearch Leading to Remote Code Execution
- CVE-2026-72642 Use of Out-of-range Pointer Offset in the Elasticsearch Machine Learning Native Inference Process
Sources
Also known as BIT-elasticsearch-2026-72639, CLEANSTART-2026-BL83922, CLEANSTART-2026-VC47751, GHSA-m2jm-f3w6-vg8c, MINI-2hq5-fprf-qcp6, MINI-48gq-p39w-j3x6 and 5 more.