CVE-2023-36420

Code execution via malformed TDS packet double-free

Published Oct 10, 2023 · Updated Apr 14, 2025

Double-free in SQL Server 2019 and 2022 and ODBC Drivers 17 and 18 allows local users to execute code through a malformed TDS packet. The SQL Server security infrastructure mishandles malformed TDS input and releases the same allocation twice; Microsoft has not named the affected function. Exploitation requires user interaction but no prior privileges and can compromise confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in SQL Server 2019 and 2022 and ODBC Drivers 17 and 18 allows local users to execute code through a malformed TDS packet. The SQL Server security infrastructure mishandles malformed TDS input and releases the same allocation twice; Microsoft has not named the affected function. Exploitation requires user interaction but no prior privileges and can compromise confidentiality, integrity, and availability.

The record

CVE
CVE-2023-36420
Published
Oct 10, 2023
Updated
Apr 14, 2025
Vendor
Microsoft
Product
Microsoft ODBC Driver 18 for SQL Server
Classifications
CWE-415, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 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=18.0.0.0 <18.3.2.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft ODBC Driver 18 for SQL Serverversion=18.0.0.0 <18.3.2.1
Microsoft · Microsoft SQL Server 2022version=15.0.0 <16.0.4080.1; version=16.0.0 <16.0.1105.1
Microsoft · Microsoft SQL Server 2019version=15.0.0 <15.0.2104.1; version=15.0.0 <15.0.4326.1
Microsoft · Microsoft ODBC Driver 17 for SQL Serverversion=17.0.0.0 <17.10.5.1

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
T1203Exploitation for Client Execution

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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