CVE-2021-46661Public exploit

Database service crash via null subquery dereference

Published Feb 1, 2022 · Updated Aug 4, 2024

Denial of service in MariaDB Server 10.5.9 and earlier allows local users to crash the database service with a crafted unused CTE. In find_field_in_tables, the optimizer dereferences the master unit's subquery Item without checking for null when resolving a view referenced only inside an unused CTE. An account able to execute SQL and create the prerequisite table and view can abort the server, interrupting database availability.

CVSS severity5.5
Medium
EPSS probability0.40%
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 MariaDB Server 10.5.9 and earlier allows local users to crash the database service with a crafted unused CTE. In find_field_in_tables, the optimizer dereferences the master unit's subquery Item without checking for null when resolving a view referenced only inside an unused CTE. An account able to execute SQL and create the prerequisite table and view can abort the server, interrupting database availability.

The record

CVE
CVE-2021-46661
Published
Feb 1, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 1, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/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.

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

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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