CVE-2026-72636 Uncontrolled Recursion in Elasticsearch Wildcard Matching Leading to Denial of Service
Attackers can crash Elasticsearch nodes by sending search requests with complex wildcard patterns that cause uncontrolled recursion and stack overflow.
- 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-2026-72636?
CVE-2026-72636 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 the Elasticsearch wildcard matching helper can lead to a denial of service via Excessive Allocation (CAPEC-130). The matcher used to resolve wildcard patterns against names is implemented recursively and had no bound on recursion depth or on the total number of match operations performed. A search request containing a wildcard pattern with a large number of wildcard groups, evaluated against a sufficiently long name, exhausts the thread stack. Elasticsearch treats a stack overflow as an unrecoverable condition and shuts the node down, so the request terminates the affected node rather than failing gracefully.
Weakness: CWE-674
Which versions are affected by CVE-2026-72636?
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-2026-72636?
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-2026-72636 being exploited?
There is no known exploitation of CVE-2026-72636 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-2026-72636, CLEANSTART-2026-EG30881, CLEANSTART-2026-ZW02426, GHSA-mmpx-jcfp-p3wg, MINI-2jh4-77g6-qpm4, MINI-2qgp-7v3g-cpvm and 20 more.