Key points
- The flaw is rated critical with a CVSS score of 9.8 due to remote code execution risks.
- Affected systems include specific builds of Windows 10 versions 1809, 21H2, 22H2 and Windows 11 23H2, 24H2.
- Microsoft has provided updates; users must install the specific version numbers listed in the advisory to be protected.
Microsoft has released security updates to address a critical vulnerability in the Windows Text Shaping component. The flaw, identified as CVE-2026-102210, allows an unauthorized attacker to execute code over a network. According to the National Vulnerability Database, the issue stems from a heap-based buffer overflow. This type of error occurs when software writes data beyond the allocated memory space, potentially allowing attackers to take control of the system.
In plain English
The Windows Text Shaping feature helps the operating system display text correctly on screens. The security flaw exists within this specific component. An attacker does not need to log in or have existing credentials to exploit this weakness. They can send a specially crafted request over the network to trigger the buffer overflow. This action can lead to remote code execution, meaning the attacker can run their own programs on the affected computer. The National Vulnerability Database assigns the flaw a CVSS score of 9.8, which is the highest possible rating for severity.
The background
The vulnerability affects several versions of Microsoft Windows that have not yet received the latest updates. Specifically, Windows 10 Version 1809 systems running builds before 10.0.17763.9376 are at risk. Windows 10 Version 21H2 and Version 22H2 are affected if they are running builds before 10.0.19044.7807. For Windows 11, Version 23H2 systems are vulnerable if they are before build 10.0.22631.7652. Windows 11 Version 24H2 is affected if running before build 10.0.26100.9711. As Patch Herald reported on October 11, 2026, other software vendors like PaperCut have also faced remote code execution issues recently, highlighting the ongoing need for vigilance.
What changes now
Microsoft has confirmed that fixes are available for all affected versions. Users must update their systems to the specific build numbers listed in the official advisory. Installing these updates patches the heap-based buffer overflow in the Text Shaping component. This prevents attackers from exploiting the memory error to run unauthorized code. Organizations should verify that their devices have successfully installed the correct versions to ensure protection.
Who needs to act first
Teams usually prioritize systems that are exposed to external networks or handle sensitive data. Check whether your current builds match the vulnerable versions listed by Microsoft. Roll out the update to a small group of test machines first to ensure compatibility with your business applications. Back up critical data before installing major updates to prevent any potential issues. If you cannot update immediately, restrict network access to these systems to reduce the risk of exploitation until the patch is applied.
What to do and how to stay safe: Microsoft
- Verify your current Windows build number by checking system settings against the affected versions listed in the advisory.
- Install the latest security updates from Microsoft to ensure your system has the patched build version.
- Monitor network traffic for unusual activity that could indicate an attempt to exploit the text shaping component.
- Ensure your backup solutions are current in case you need to restore systems after applying the update.
Step-by-step guide: Out-of-Band Patches: Meaning, Risks, and Deployment Reality
General security guidance from the Patch Herald newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-102210?
It is a heap-based buffer overflow vulnerability in the Windows Text Shaping component that allows remote code execution.
Is this vulnerability critical?
Yes, the National Vulnerability Database rates it as critical with a CVSS score of 9.8.
Which Windows versions are affected?
Windows 10 versions 1809, 21H2, and 22H2, as well as Windows 11 versions 23H2 and 24H2, are affected if they are below the specified build numbers.
