# CVE-2026-72639: Memory Allocation with Excessive Size Value in Elasticsearch Highlighting Leading to Denial of Service

> An authenticated user can cause a denial of service in Elasticsearch by submitting a search request with an excessive highlighting count, leading to memory exhaustion and node termination.

- **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:** 13 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** BIT-elasticsearch-2026-72639, CLEANSTART-2026-BL83922, CLEANSTART-2026-VC47751, GHSA-m2jm-f3w6-vg8c, MINI-2hq5-fprf-qcp6, MINI-48gq-p39w-j3x6, MINI-73fq-m86m-7mm3, MINI-8xq3-fcfq-fc8q, MINI-cg6x-3qvv-wfrg, MINI-f88v-62fm-6vxx, MINI-h32c-rh78-m45g

## What is CVE-2026-72639?

CVE-2026-72639 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

Elasticsearch does not enforce an upper bound on a user-supplied count accepted by a search highlighting option, and the allocation derived from that count is not accounted against any circuit breaker. An authenticated user holding only read privileges on a single searchable index can submit one small search request that causes the node to reserve an excessively large internal data structure. The allocation occurs before the existing highlighting safety limits are evaluated, so memory exhaustion raises a fatal error that terminates the Elasticsearch node process. This results in a denial of service for the affected node and degrades cluster routing and health. The defect is not volumetric and does not depend on the size of the indexed data, so a single request is sufficient.

Weakness: CWE-789 (Memory Allocation with Excessive Size Value)

## Which versions are affected by CVE-2026-72639?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `elasticsearch` | Bitnami | From 8.19.0 | 8.19.20, 9.5.1 |

Products: Elastic Elasticsearch.

## How do I fix CVE-2026-72639?

Upgrade elasticsearch to a fixed version for your release line: 8.19.20 or 9.5.1.

## Is CVE-2026-72639 being exploited?

There is no known exploitation of CVE-2026-72639 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-2026-72639 and fix it if it is affected.

What it is: CVE-2026-72639 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.
Exploitation: There is no known exploitation of CVE-2026-72639 in the wild and no public exploit code.

Affected packages and fixed versions:
- elasticsearch (Bitnami): affected from 8.19.0; fixed in 8.19.20, 9.5.1

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-2026-72639/ (Markdown: https://insights.sbomify.com/CVE-2026-72639/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72639
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72639
- OSV: https://osv.dev/vulnerability/CVE-2026-72639

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72639/
Summaries are generated and may contain mistakes; the official description above is the record.