CVE-2021-2006Network attack vector

Authenticated client hang or repeatable crash

Published Jan 20, 2021 · Updated Sep 26, 2024

Denial of service in the C API of Oracle MySQL Client 8.0.19 and earlier allows remote authenticated users to hang or crash clients. Oracle has not published the specific C API operation or malformed protocol input that triggers the failure. Exploitation requires low privileges, network access over a supported protocol, and high attack complexity; success affects availability only through a hang or repeatable client crash.

CVSS severity5.3
Medium
EPSS probability1.82%
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 C API of Oracle MySQL Client 8.0.19 and earlier allows remote authenticated users to hang or crash clients. Oracle has not published the specific C API operation or malformed protocol input that triggers the failure. Exploitation requires low privileges, network access over a supported protocol, and high attack complexity; success affects availability only through a hang or repeatable client crash.

The record

CVE
CVE-2021-2006
Published
Jan 20, 2021
Updated
Sep 26, 2024
Vendor
Oracle Corporation
Product
MySQL Server
Classifications
T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 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=8.0.19 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Oracle Corporation · MySQL Serverversion=8.0.19 and prior

Published CVSS scores

6.3NIST NVDAV:N/AC:M/Au:S/C:N/I:N/A:C
5.3Oracle CorporationCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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