CVE-2021-2011Network attack vector

Client denial of service via undisclosed C API

Published Jan 20, 2021 · Updated Sep 26, 2024

Denial of service in the MySQL Client C API in MySQL 5.7.32 and earlier and 8.0.22 and earlier allows remote attackers to crash or hang clients. Oracle has not published the affected C API function or the operation it performs incorrectly on network input. Exploitation requires no credentials or user interaction but has high attack complexity, and the reported consequence is limited to client availability.

CVSS severity5.9
Medium
EPSS probability3.03%
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 MySQL Client C API in MySQL 5.7.32 and earlier and 8.0.22 and earlier allows remote attackers to crash or hang clients. Oracle has not published the affected C API function or the operation it performs incorrectly on network input. Exploitation requires no credentials or user interaction but has high attack complexity, and the reported consequence is limited to client availability.

The record

CVE
CVE-2021-2011
Published
Jan 20, 2021
Updated
Sep 26, 2024
Vendor
Oracle Corporation
Product
MySQL Server
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

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=5.7.32 and prior
  2. Affected versionversion=8.0.22 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · MySQL Serverversion=5.7.32 and prior; version=8.0.22 and prior

Published CVSS scores

5.9Oracle CorporationCVSS:3.1/AV:N/AC:H/PR:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application 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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