---
id: "CVE-2026-101799"
kind: "vulnerability"
aliases: ["CVE-2026-101799"]
title: "MySQL Server: Group Replication flaw lets an adjacent attacker crash the server"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["database", "group-replication", "mysql", "package", "self-hosted"]
not_affected_if: ["isolated-network", "standalone-server"]
published_at: "2026-10-20T22:18:35+00:00"
first_seen_at: "2026-10-23T21:57:23+00:00"
updated_at: "2026-10-25T03:53:40+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-101799", "first_seen_at": "2026-10-23T21:57:23+00:00"}]
---

# MySQL Server: Group Replication flaw lets an adjacent attacker crash the server

A flaw in the Group Replication GCS component of MySQL Server and MySQL Cluster lets an unauthenticated attacker on the same network segment hang or repeatedly crash the server. The impact is denial of service only, with no data read or code execution stated.

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

## How to check

- Run `SELECT @@version;` in the MySQL client and compare against the affected ranges: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1.
- Check whether Group Replication is in use with `SELECT * FROM performance_schema.replication_group_members;`

## Fix

- Upgrade MySQL Server 8.4.x to a release after `8.4.12`, 9.7.x to a release after `9.7.3`, or 26.7.x to a release after `26.7.1`.
- Upgrade MySQL Cluster 8.0.x to a release after `8.0.49`.
- Oracle's patch version numbers are unknown from the sources.

## Timeline

- 2026-10-23T21:57:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-101799

## From the sources

Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Group Replication GCS).  Supported versions that are affected are MySQL Server: 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1; MySQL Cluster: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3 and  26.7.0-26.7.1. Easily exploitable vulnerability allows unauthenticated attacker with access to the physical communication segment attached to the hardware where the MySQL Server, MySQL Cluster executes 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:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

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