CVE-2023-24903Network attack vector

Remote code execution via SSTP double-free race

Published May 9, 2023 · Updated Jul 10, 2025

Double-free in Microsoft Windows SSTP allows remote attackers to execute code on an SSTP server using crafted SSTP packets. The SSTP packet-processing path can release the same allocation twice when concurrent malicious packets trigger a race condition; Microsoft has not disclosed a function-level locus. Exploitation requires an unauthenticated network path to an SSTP server and winning the race, after which code runs on the server.

CVSS severity8.1
High
EPSS probability0.92%
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 Microsoft Windows SSTP allows remote attackers to execute code on an SSTP server using crafted SSTP packets. The SSTP packet-processing path can release the same allocation twice when concurrent malicious packets trigger a race condition; Microsoft has not disclosed a function-level locus. Exploitation requires an unauthenticated network path to an SSTP server and winning the race, after which code runs on the server.

The record

CVE
CVE-2023-24903
Published
May 9, 2023
Updated
Jul 10, 2025
Vendor
Microsoft
Product
Windows 10 Version 1507
Classifications
CWE-362, CWE-415, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 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=10.0.10240.0 <10.0.10240.19926

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 10 Version 1507version=10.0.10240.0 <10.0.10240.19926
Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.4377
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.5921
Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.1936
Microsoft · Windows Server 2012 (Server Core installation)version=6.2.9200.0 <6.2.9200.24266
Microsoft · Windows Server 2012version=6.2.9200.0 <6.2.9200.24266
Microsoft · Windows 10 Version 21H2version=10.0.19043.0 <10.0.19044.2965
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.5921
Microsoft · Windows Server 2008 R2 Service Pack 1version=6.1.7601.0 <6.1.7601.26519
Microsoft · Windows 10 Version 20H2version=10.0.0 <10.0.19042.2965
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)version=6.1.7601.0 <6.1.7601.26519
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.2965
Microsoft · Windows Server 2012 R2 (Server Core installation)version=6.3.9600.0 <6.3.9600.20969
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.4377
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.1702
Microsoft · Windows 10 Version 1607version=10.0.14393.0 <10.0.14393.5921
Microsoft · Windows Server 2008 Service Pack 2version=6.0.6003.0 <6.0.6003.22070
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.1726
Microsoft · Windows 10 Version 1809version=10.0.0 <10.0.17763.4377; version=10.0.17763.0 <10.0.17763.4377
Microsoft · Windows Server 2012 R2version=6.3.9600.0 <6.3.9600.20969
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)version=6.0.6003.0 <6.0.6003.22070

Published CVSS scores

7.1Microsoft CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
8.1Microsoft CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-415Double Free
T1190Exploit Public-Facing Application

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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