CVE-2024-0056Network attack vector

Credential theft via SQL encryption downgrade

Published Jan 9, 2024 · Updated Jun 3, 2025

Information disclosure in Microsoft.Data.SqlClient and System.Data.SqlClient allows man-in-the-middle attackers to steal SQL credentials. The providers accept a downgraded pre-login encryption negotiation, allowing an intermediary to replace protected transport with plaintext. Exploitation requires interception between the SQL client and server; affected applications can disclose database credentials despite requesting TLS.

CVSS severity8.7
High
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Microsoft.Data.SqlClient and System.Data.SqlClient allows man-in-the-middle attackers to steal SQL credentials. The providers accept a downgraded pre-login encryption negotiation, allowing an intermediary to replace protected transport with plaintext. Exploitation requires interception between the SQL client and server; affected applications can disclose database credentials despite requesting TLS.

The record

CVE
CVE-2024-0056
Published
Jan 9, 2024
Updated
Jun 3, 2025
Vendor
Microsoft
Product
Microsoft .NET Framework 3.5 and 4.8.1
Classifications
CWE-319, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record 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=4.8.1 <4.8.09214.01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft .NET Framework 3.5 and 4.8.1version=4.8.1 <4.8.09214.01
Microsoft · .NET 6.0version=6.0.0 <6.0.26
Microsoft · Microsoft .NET Framework 3.5 and 4.8version=4.8.0 <4.8.04690.02
Microsoft · System.Data.SqlClientversion=1.0 <4.8.6
Microsoft · Microsoft Visual Studio 2022 version 17.8version=17.8.0 <17.8.4
Microsoft · Microsoft Visual Studio 2022 version 17.6version=17.6.0 <17.6.11
Microsoft · Microsoft Visual Studio 2022 version 17.4version=17.4.0 <17.4.15
Microsoft · .NET 8.0version=8.0 <8.0.1
Microsoft · Microsoft .NET Framework 2.0 Service Pack 2version=2.0.0 <3.0.50727.8976
Microsoft · Microsoft SQL Server 2022version=0 <16.0.4100.1; version=16.0.0 <16.0.1110.1
Microsoft · Microsoft Visual Studio 2022 version 17.2version=17.2.0 <17.2.23
Microsoft · Microsoft.Data.SqlClientversion=2.0 <2.1.7; version=3.0 <3.1.5; version=4.0 <4.0.5; version=5.0 <5.1.3
Microsoft · .NET 7.0version=7.0.0 <7.0.15
Microsoft · Microsoft .NET Framework 3.5 and 4.7.2version=4.7.0 <4.7.04081.03
Microsoft · Microsoft .NET Frameworkversion=4.7.0 <4.7.04081.02
Microsoft · Microsoft .NET Framework 4.8version=4.8.0 <4.8.04690.02

Published CVSS scores

8.7Microsoft CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-319Cleartext Transmission of Sensitive Information
T1557Adversary-in-the-Middle

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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