CVE-2023-21866Network attack vector

Authenticated service interruption through optimizer processing

Published Jan 17, 2023 · Updated Sep 17, 2024

Denial of service in Oracle MySQL Server 8.0.28 and earlier allows remote authenticated users to hang or repeatedly crash the server. Oracle identifies Server: Optimizer as the affected component but has not published the operation or crafted input that triggers the failure. Exploitation requires high privileges and network access through the MySQL Protocol, and the reported consequence is limited to service availability.

CVSS severity4.9
Medium
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Oracle MySQL Server 8.0.28 and earlier allows remote authenticated users to hang or repeatedly crash the server. Oracle identifies Server: Optimizer as the affected component but has not published the operation or crafted input that triggers the failure. Exploitation requires high privileges and network access through the MySQL Protocol, and the reported consequence is limited to service availability.

The record

CVE
CVE-2023-21866
Published
Jan 17, 2023
Updated
Sep 17, 2024
Vendor
Oracle Corporation
Product
MySQL Server
Classifications
T1499.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jan 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.0.28 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Oracle Corporation · MySQL Serverversion=8.0.28 and prior

Published CVSS scores

4.9Oracle CorporationCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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