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).

A flaw was found in the Group Replication GCS component of MySQL. This issue may allow an attacker to impact the confidentiality, integrity, and/or availability of MySQL Server depending on the vulnerability details. Refer to the Oracle CPU advisory for component-specific impact.

This vulnerability is rated as Moderate rather than Important because exploitation is constrained to adjacent network access and specifically targets deployments running the optional Group Replication feature. In default Red Hat Enterprise Linux environments, MySQL does not enable or load the Group Replication plugin out of the box, significantly limiting exposure on typical systems. Successful exploitation allows an unauthenticated attacker on the same physical or logical network segment to trigger a denial of service by crashing the database service, without compromising data confidentiality or integrity. Red Hat Enterprise Linux 10 Affected mysql8.4 Red Hat Enterprise Linux 6 Not affected mysql Red Hat Enterprise Linux 9 Affected mysql Red Hat Hardened Images Not affected mariadb10.11 Red Hat Hardened Images Not affected mariadb11.8 https://www.cve.org/CVERecord?id=CVE-2026-101799 https://nvd.nist.gov/vuln/detail/CVE-2026-101799 https://www.oracle.com/security-alerts/cpuoct2026.html