CVE-2026-21965 Denial of service in MySQL Server

Low 2.7 Published 20 Jan 2026 Updated 21 Jan 2026

High-privileged attackers can cause a partial denial of service in MySQL Server via the Pluggable Auth component.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-21965?

CVE-2026-21965 is a low-severity denial of service vulnerability in Oracle Mysql Server, published on 20 Jan 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Pluggable Auth). Supported versions that are affected are 9.0.0-9.5.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of MySQL Server. CVSS 3.1 Base Score 2.7 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L).

Which versions are affected by CVE-2026-21965?

It affects 1 product.

Products include Oracle Mysql Server.

How do I fix CVE-2026-21965?

No fix has been published for CVE-2026-21965 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-21965 being exploited?

There is no known exploitation of CVE-2026-21965 in the wild and no public exploit code.

All Oracle Mysql Server vulnerabilities

Sources

Also known as GHSA-j7pc-6x9v-m63m, MINI-6g25-6jpc-m8m6, MINI-8v3c-h6pq-rg5w, MINI-h39q-957r-85wp, UBUNTU-CVE-2026-21965.