CVE-2026-72638 Uncontrolled Recursion in Elasticsearch Leading to Denial of Service
An authenticated user with low privileges can cause a denial of service in Elasticsearch by submitting a malformed custom analysis definition that triggers uncontrolled recursion.
- 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-2026-72638?
CVE-2026-72638 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
Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). An authenticated user holding only low-privileged index creation permissions can submit a single request containing a specially crafted, malformed custom analysis definition that is resolved recursively without a cycle or depth check, exhausting the thread stack and terminating the affected node.
Weakness: CWE-674
Which versions are affected by CVE-2026-72638?
1 open source package ship an affected version, including elasticsearch. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
elasticsearch Bitnami | From 8.0.0 | 8.19.20, 9.4.5 |
Products include Elastic Elasticsearch.
How do I fix CVE-2026-72638?
Upgrade elasticsearch to a fixed version for your release line: 8.19.20 or 9.4.5.
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-2026-72638 being exploited?
There is no known exploitation of CVE-2026-72638 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-2026-72638, CLEANSTART-2026-OO18479, CLEANSTART-2026-PP64708, GHSA-rx34-f5m9-h9p5, MINI-27p8-gpv6-pjfq, MINI-55rr-j72r-mf7r and 20 more.