# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jul 2026
- **Updated:** 22 Jul 2026
- **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, MINI-3gx2-r9j2-xh9q, MINI-45wj-4j8q-jrx8, MINI-6592-m6wq-5rcw, MINI-6884-fvf4-37vm, MINI-7vww-85rx-2j6r, MINI-9p82-7f9v-qfp4, MINI-fhhr-x47v-3m4c, MINI-fqc4-66fg-qgm5, MINI-fr99-r9jm-433g, MINI-gcr2-9jh8-v864, MINI-h3jf-658m-cw8x, MINI-mvx9-5q5q-rc6f, MINI-p3rc-4mh2-pmj9, MINI-p9xv-29jh-fm47, MINI-ph77-mmmp-qpwq, MINI-rqjm-mjhv-24pv, MINI-vhrc-5948-g4mw, MINI-vmqj-9rh7-q3mg, MINI-xc3q-qcx5-3ppq, MINI-xv5j-g6rr-3cjv

## 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 (Reachable Assertion)

## Which versions are affected by CVE-2026-63140?

1 open source package ship an affected version, including elasticsearch. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `elasticsearch` | Bitnami | From 8.0.0 | 8.19.19, 9.3.8, 9.4.4 |

Products: 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.

## 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](https://insights.sbomify.com/CVE-2015-1427/): Elasticsearch Groovy Scripting Engine Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2014-3120](https://insights.sbomify.com/CVE-2014-3120/): Elasticsearch Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2015-5377](https://insights.sbomify.com/CVE-2015-5377/): Code injection in n/a (critical 9.8)
- [CVE-2026-72649](https://insights.sbomify.com/CVE-2026-72649/): Deserialization of Untrusted Data in Elasticsearch Leading to Remote Code Execution (high 8.8)
- [CVE-2026-72642](https://insights.sbomify.com/CVE-2026-72642/): Use of Out-of-range Pointer Offset in the Elasticsearch Machine Learning Native Inference Process (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63140 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-63140 in the wild and no public exploit code.

Affected packages and fixed versions:
- elasticsearch (Bitnami): affected from 8.0.0; fixed in 8.19.19, 9.3.8, 9.4.4

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63140/ (Markdown: https://insights.sbomify.com/CVE-2026-63140/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63140
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63140
- OSV: https://osv.dev/vulnerability/CVE-2026-63140

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63140/
Summaries are generated and may contain mistakes; the official description above is the record.