Description
Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Optimizer). 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 high privileged attacker with network access via multiple protocols 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 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).
Published: 2026-10-20
Score: 4.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service
Action: Immediate Patch
AI Analysis

Impact

A flaw in the Optimizer component of Oracle MySQL Server and MySQL Cluster enables a high privileged attacker who has network access via multiple protocols to induce a hang or complete crash of the database server, resulting in a denial of service. The vulnerability has a CVSS v3.1 Base Score of 4.9, indicating a medium overall severity that mainly compromises availability while leaving confidentiality and integrity untouched.

Affected Systems

Affected vendors include Oracle Corporation, specifically the MySQL Server and MySQL Cluster products. The vulnerable releases are MySQL Server 8.4.0‑8.4.12, 9.7.0‑9.7.3, and 26.7.0‑26.7.1, and 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.

Risk and Exploitability

The CVSS score of 4.9 reflects a moderate risk that, coupled with the very low EPSS (< 1%) and absence of a KEV listing, suggests the vulnerability is not widely exploited yet. Because the flaw requires high privileges and network access, an attacker who successfully leverages it can repeatedly bring the server offline, disrupting any services dependent on the database. The primary fix is to apply Oracle patches for affected MySQL Server and Cluster releases, and additional mitigations include restricting network access to MySQL ports, monitoring for service restarts, and disabling unneeded protocols until the patch is deployed.

Generated by OpenCVE AI on October 23, 2026 at 06:15 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest Oracle patches for MySQL Server and MySQL Cluster to eliminate the optimizer flaw
  • Restrict network access to MySQL ports to trusted hosts or VPNs to reduce the attack surface until the patch is deployed
  • Configure automated monitoring and recovery scripts to detect and restart the MySQL service after crashes to maintain availability

Generated by OpenCVE AI on October 23, 2026 at 06:15 UTC.

Tracking

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Advisories

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History

Fri, 23 Oct 2026 05:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-399
CWE-400

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
Title Denial of Service Vulnerability in MySQL Server and Cluster Optimizer mysql: mysql: Denial of Service via Server Optimizer flaw
Weaknesses CWE-835
References
Metrics threat_severity

None

 threat_severity

Moderate

Thu, 22 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 21 Oct 2026 02:45:00 +0000

Type Values Removed Values Added
Title Denial of Service Vulnerability in MySQL Server and Cluster Optimizer
Weaknesses CWE-399
CWE-400

Tue, 20 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
Description Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Optimizer). 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 high privileged attacker with network access via multiple protocols 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 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).
First Time appeared Oracle
Oracle mysql Cluster
Oracle mysql Server
CPEs cpe:2.3:a:oracle:mysql_cluster:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:mysql_server:*:*:*:*:*:*:*:*
Vendors & Products Oracle
Oracle mysql Cluster
Oracle mysql Server
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Oracle Mysql Cluster Mysql Server
cve-icon MITRE

Status: PUBLISHED

Assigner: oracle

Published:

Updated: 2026-10-22T17:21:17.289Z

Reserved: 2026-09-28T15:40:09.506Z

Link: CVE-2026-101787

cve-icon Vulnrichment

Updated: 2026-10-22T17:02:24.312Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-20T22:18:34.403

Modified: 2026-10-22T18:17:23.320

Link: CVE-2026-101787

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-20T21:22:55Z

Links: CVE-2026-101787 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T06:15:13Z

Weaknesses
  • CWE-284

    Improper Access Control

  • CWE-835

    Loop with Unreachable Exit Condition ('Infinite Loop')