Oracle MySQL Server up to 9.1.0 Optimizer improper authorization

Summaryinfo

A vulnerability labeled as critical has been found in Oracle MySQL Server up to 9.1.0. The affected element is an unknown function of the component Optimizer. The manipulation results in improper authorization. This vulnerability was named CVE-2025-21566. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Oracle MySQL Server up to 9.1.0. It has been classified as critical. Affected is an unknown part of the component Optimizer. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on availability. CVE summarizes:

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 9.1.0 and prior. Easily exploitable vulnerability allows low 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 hang or frequently repeatable crash (complete DOS) of MySQL Server. 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).

The advisory is shared for download at oracle.com. This vulnerability is traded as CVE-2025-21566 since 12/25/2024. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 01/09/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

The vulnerability scanner Nessus provides a plugin with the ID 247050 (Linux Distros Unpatched Vulnerability : CVE-2025-21566), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (247050) and CERT Bund (WID-SEC-2025-0167). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Oracle MySQL
• Debian Linux
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• NetApp ActiveIQ Unified Manager
• RESF Rocky Linux
• MariaDB MariaDB

Productinfo

Type

• Database Software

Vendor

• Oracle

Name

• MySQL Server

Version

• 9.0
• 9.1.0

License

• open-source

Website

• Vendor: https://www.oracle.com

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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