CVE-2026-21929Network attack vector

Authenticated server crash

Published Jan 20, 2026 · Updated Jan 20, 2026

Denial of service in the MySQL Server parser in versions 9.0.0 through 9.5.0 allows remote authenticated users to crash the server. Oracle identifies the Server: Parser component but has not published the malformed input, parser routine, or incorrect operation that triggers the failure. A low-privileged account and network access over a supported protocol are required, and exploitation causes a hang or frequently repeatable crash without reported data disclosure or modification.

CVSS severity5.3
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in the MySQL Server parser in versions 9.0.0 through 9.5.0 allows remote authenticated users to crash the server. Oracle identifies the Server: Parser component but has not published the malformed input, parser routine, or incorrect operation that triggers the failure. A low-privileged account and network access over a supported protocol are required, and exploitation causes a hang or frequently repeatable crash without reported data disclosure or modification.

The record

CVE
CVE-2026-21929
Published
Jan 20, 2026
Updated
Jan 20, 2026
Vendor
Oracle
Product
MySQL Server
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=9.0.0 <=9.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Oracle · MySQL Serverversion=9.0.0 <=9.5.0

Published CVSS scores

5.3OracleCVSS:3.1/AV:N/AC:H/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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo