---
id: CVE-2026-63140
title: >-
  Reachable Assertion (CWE-617) in Elasticsearch can lead to denial of service
  via Input Data Manipulation (CAPEC-153)
summary: >-
  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 b…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-617
vendor: elastic
product: elasticsearch
affected:
  - 'elasticsearch >= 8.0.0, < 8.19.19'
  - 'elasticsearch >= 9.0.0, < 9.3.8'
  - 'elasticsearch >= 9.4.0, < 9.4.4'
patched:
  - elasticsearch 9.4.4
published: '2026-07-21'
updated: '2026-08-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63140'
references:
  - url: >-
      https://discuss.elastic.co/t/elasticsearch-8-19-19-9-3-8-9-4-4-security-update-esa-2026-64/388565
    label: security@elastic.co
tags:
  - nvd
epss: 0.0042
epssPercentile: 0.33599
ingestedAt: '2026-08-07T23:18:01.329Z'
---

## Overview

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.

## Affected

- `elasticsearch >= 8.0.0, < 8.19.19`
- `elasticsearch >= 9.0.0, < 9.3.8`
- `elasticsearch >= 9.4.0, < 9.4.4`

## Remediation

Upgrade past the affected range:

- `elasticsearch 9.4.4`