CVE-2025-21500Network attack vector

Authenticated server hang or repeatable crash

Published Jan 21, 2025 · Updated Nov 3, 2025

Denial of service in MySQL Server 8.0.40 and earlier, 8.4.3 and earlier, and 9.1.0 and earlier allows remote authenticated users to cause crashes. Oracle identifies the Server Optimizer as the affected component but has not disclosed the faulty operation or triggering input. Reachability requires a low-privileged database account and network access; successful exploitation hangs or repeatedly crashes the server without reported data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability1.02%
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 MySQL Server 8.0.40 and earlier, 8.4.3 and earlier, and 9.1.0 and earlier allows remote authenticated users to cause crashes. Oracle identifies the Server Optimizer as the affected component but has not disclosed the faulty operation or triggering input. Reachability requires a low-privileged database account and network access; successful exploitation hangs or repeatedly crashes the server without reported data disclosure or modification.

The record

CVE
CVE-2025-21500
Published
Jan 21, 2025
Updated
Nov 3, 2025
Vendor
Oracle Corporation
Product
MySQL Server
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=* <=8.0.40
  2. Affected versionversion=* <=8.4.3
  3. Affected versionversion=* <=9.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Oracle Corporation · MySQL Serverversion=* <=8.0.40; version=* <=8.4.3; version=* <=9.1.0

Published CVSS scores

6.5Oracle CorporationCVSS:3.1/AV:N/AC:L/PR:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
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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