CVE-2023-21556

Name: CVE-2023-21556
Creator: NVD / NIST
Published: 2023-01-10T22:15:15.843+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 1.46%

Last modified Jun 17, 2026

CVE-2023-21556 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability. EPSS estimates a 1.46% chance of exploitation in the next 30 days.

Description

Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability

Metrics

CVSS 3.1

8.1/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.46%

70.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-191

Affected Software

Vendor	Product	Versions	Update
Microsoft	Windows 10 1607	All versions	—
Microsoft	Windows 10 1809	All versions	—
Microsoft	Windows 10 20h2	All versions	—
Microsoft	Windows 10 21h2	All versions	—
Microsoft	Windows 10 22h2	All versions	—
Microsoft	Windows 11 21h2	All versions	—
Microsoft	Windows 11 22h2	All versions	—
Microsoft	Windows 7	All versions	Sp1
Microsoft	Windows 8.1	All versions	—
Microsoft	Windows Rt 8.1	All versions	—
Microsoft	Windows Server 2008	All versions	Sp2
Microsoft	Windows Server 2008	r2	Sp1
Microsoft	Windows Server 2012	All versions	—
Microsoft	Windows Server 2012	r2	—
Microsoft	Windows Server 2016	All versions	—
Microsoft	Windows Server 2019	All versions	—
Microsoft	Windows Server 2022	All versions	—

References

Timeline

Published: Jan 10, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-21556?

Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability

How severe is CVE-2023-21556?

CVE-2023-21556 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 1.46% probability of exploitation in the next 30 days.

How do I fix CVE-2023-21556?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-21556?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST