CVE-2026-63140 Reachable Assertion in Elasticsearch Leading to Denial of Service
A low-privileged user can crash an Elasticsearch node by sending a crafted search request with a null value, causing denial of service.
- 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-2026-63140?
CVE-2026-63140 is a medium-severity denial of service vulnerability in Elastic Elasticsearch, published on 21 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Reachable Assertion (CWE-617) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). A specially crafted search request containing a null value in a specific query clause causes an internal assertion to be raised during query parsing. Because Elasticsearch treats assertion failures as fatal errors, this terminates the affected node process. A low-privileged authenticated user with read access to at least one index can exploit this condition with a single request to cause a node to terminate, disrupting search availability. In a single-node deployment this fully stops Elasticsearch; in a multi-node cluster it reduces cluster capacity for each affected node.
Weakness: CWE-617
Which versions are affected by CVE-2026-63140?
1 open source package ship an affected version, including elasticsearch. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
elasticsearch Bitnami | From 8.0.0 | 8.19.19, 9.3.8, 9.4.4 |
Products include Elastic Elasticsearch.
How do I fix CVE-2026-63140?
Upgrade elasticsearch to a fixed version for your release line: 8.19.19, 9.3.8 or 9.4.4.
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-2026-63140 being exploited?
There is no known exploitation of CVE-2026-63140 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-2026-63140, CLEANSTART-2026-PM70424, CLEANSTART-2026-ZU18134, GHSA-h663-9fgh-w7xf, MINI-26v7-69j8-6fc4, MINI-2c2w-w7v6-qhh9 and 20 more.