---
id: "CVE-2026-101620"
kind: "vulnerability"
aliases: ["CVE-2026-101620"]
title: "MySQL Server optimizer flaw lets low-privileged users crash the server"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["databases", "mysql", "package", "self-hosted"]
not_affected_if: ["no-network-access", "unaffected-version"]
published_at: "2026-10-20T22:18:15+00:00"
first_seen_at: "2026-10-23T21:57:22+00:00"
updated_at: "2026-10-25T03:55:09+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-101620", "first_seen_at": "2026-10-23T21:57:22+00:00"}]
---

# MySQL Server optimizer flaw lets low-privileged users crash the server

A flaw in the MySQL Server optimizer, affecting versions 9.7.0 through 9.7.3 of MySQL Server and MySQL Cluster, can be triggered by an authenticated low-privileged user over the network. A successful attack causes a hang or a repeatable crash, which denies service to the database.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `mysqld --version` or `SELECT VERSION();` and compare against the affected range `9.7.0` to `9.7.3`
- Check whether MySQL Cluster is in use with `ndb_mgm -e show`

## Fix

- Upgrade MySQL Server and MySQL Cluster to a release later than `9.7.3` (the sources do not name the fixed version)

## Timeline

- 2026-10-23T21:57:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-101620

## From the sources

Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Optimizer).  Supported versions that are affected are MySQL Server: 9.7.0-9.7.3; MySQL Cluster: 9.7.0-9.7.3. Easily exploitable vulnerability allows low privileged attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster.  Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 6.5 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_