CVE-2021-2367Network attack vector

Authenticated denial of service via undisclosed optimizer flaw

Published Jul 20, 2021 · Updated Sep 26, 2024

Denial of service in the Oracle MySQL Server Optimizer in 8.0.25 and earlier allows remote authenticated users to hang or crash the server. Oracle has not disclosed the optimizer operation or input that triggers the failure. High-privileged MySQL access over a supported network protocol is required, and successful exploitation affects availability only.

CVSS severity4.9
Medium
EPSS probability2.59%
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 the Oracle MySQL Server Optimizer in 8.0.25 and earlier allows remote authenticated users to hang or crash the server. Oracle has not disclosed the optimizer operation or input that triggers the failure. High-privileged MySQL access over a supported network protocol is required, and successful exploitation affects availability only.

The record

CVE
CVE-2021-2367
Published
Jul 20, 2021
Updated
Sep 26, 2024
Vendor
Oracle Corporation
Product
MySQL Server
Classifications
T1499.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jul 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 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=8.0.25 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Oracle Corporation · MySQL Serverversion=8.0.25 and prior

Published CVSS scores

4.9OracleCVSS: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

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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