Oracle MySQL Server up to 8.0.44/8.4.7/9.5.0 Optimizer denial of service

Summaryinfo

A vulnerability has been found in Oracle MySQL Server up to 8.0.44/8.4.7/9.5.0 and classified as problematic. This impacts an unknown function of the component Optimizer. The manipulation leads to denial of service. This vulnerability is referenced as CVE-2026-21941. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Oracle MySQL Server up to 8.0.44/8.4.7/9.5.0. This issue affects an unknown part of the component Optimizer. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.44, 8.4.0-8.4.7 and 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 hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

The advisory is shared at oracle.com. The identification of this vulnerability is CVE-2026-21941 since 01/05/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation requires an enhanced level of successful authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 301887 (AlmaLinux 10 : mysql8.4 (ALSA-2026:4162)), 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 (301887), EUVD (EUVD-2026-3568) and CERT Bund (WID-SEC-2026-0168). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Red Hat Enterprise Linux
• Ubuntu Linux
• Oracle Linux
• RESF Rocky Linux
• Oracle MySQL

Productinfo

Type

• Database Software

Vendor

• Oracle

Name

• MySQL Server

Version

• 8.0.0
• 8.0.1
• 8.0.2
• 8.0.3
• 8.0.4
• 8.0.5
• 8.0.6
• 8.0.7
• 8.0.8
• 8.0.9
• 8.0.10
• 8.0.11
• 8.0.12
• 8.0.13
• 8.0.14
• 8.0.15
• 8.0.16
• 8.0.17
• 8.0.18
• 8.0.19
• 8.0.20
• 8.0.21
• 8.0.22
• 8.0.23
• 8.0.24
• 8.0.25
• 8.0.26
• 8.0.27
• 8.0.28
• 8.0.29
• 8.0.30
• 8.0.31
• 8.0.32
• 8.0.33
• 8.0.34
• 8.0.35
• 8.0.36
• 8.0.37
• 8.0.38
• 8.0.39
• 8.0.40
• 8.0.41
• 8.0.42
• 8.0.43
• 8.0.44
• 8.4.0
• 8.4.1
• 8.4.2
• 8.4.3
• 8.4.4
• 8.4.5
• 8.4.6
• 8.4.7
• 9.0
• 9.1
• 9.2
• 9.3
• 9.4
• 9.5.0

License

• open-source

Website

• Vendor: https://www.oracle.com

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

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Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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