# CVE-2026-63140

## Summary

- **CVE ID:** CVE-2026-63140
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-617
- **Published:** Jul 21, 2026
- **Last Modified:** Jul 24, 2026

## 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.

## Affected Products

- Elastic — Elasticsearch (9.0.0)
- Elastic — Elasticsearch (9.4.0)
- Elastic — Elasticsearch (8.0.0)

## References

- [CNA](https://discuss.elastic.co/t/elasticsearch-8-19-19-9-3-8-9-4-4-security-update-esa-2026-64/388565)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.24%
- **EPSS Percentile:** 15.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._