Urgent: Patch Windows 10/11 to Fix Critical CVE-2026-102210 Text Shaping Heap Overflow

An unauthorized attacker can execute arbitrary code on a remote Windows system by exploiting a heap-based buffer overflow in the Windows Text Shaping component. This capability, tracked as CVE-2026-102210, allows an adversary to take control of a machine without needing prior access or valid credentials. The flaw enables remote code execution directly over a network connection.

The National Vulnerability Database rates this vulnerability as critical with a CVSS score of 9.8. The weakness stems from CWE-122, a heap-based buffer overflow. This means that when the system processes text shaping data, it can write more information to a memory buffer than it can hold. This overflow allows an attacker to overwrite adjacent memory and redirect the program's execution flow to their own malicious code.

Affected Systems and Versions

Microsoft Windows 10 Version 1809 is vulnerable if it is running a build earlier than 10.0.17763.9376. Users of Windows 10 Version 21H2 and Version 22H2 face the same risk if their systems are running builds before 10.0.19044.7807. These older versions of the operating system are listed as affected by the vulnerability.

Windows 11 users are also at risk if they have not updated their systems recently. Version 23H2 is affected on builds before 10.0.22631.7652. Similarly, the latest Windows 11 Version 24H2 is vulnerable on builds before 10.0.26100.9711. Organizations should verify their current build numbers against these thresholds to determine their exposure to this critical remote execution risk.

What to watch

Small-business owners should immediately check their Windows versions and build numbers against the affected lists. Monitor vendor announcements for the release of security updates that address CVE-2026-102210. Once Microsoft provides an update, apply it to all affected workstations and servers without delay. Keep an eye on network logs for unusual outbound traffic that might indicate a compromise has already occurred.

What made it possible

Teams usually encounter this class of weakness when software fails to validate the size of incoming data before writing it to memory. The vulnerability serves the initial access stage of an intrusion, allowing attackers to breach the perimeter without physical contact. Check whether your systems process untrusted text data from network sources. Ensure that memory management controls are enforced to prevent overflows. This general approach helps mitigate risks where input validation is insufficient.

Background: Buffer overflow vulnerabilities

Watch for unexpected application crashes, specific error codes, or data corruption in logs. These signs indicate memory boundary violations. Isolate the affected service, review recent code changes, and apply backported security fixes to mitigate risk while preparing a long-term patch.

Read the full guide: Detect Buffer Overflow Vulnerabilities: Early Signs and Hidden Indicators

What to do and how to stay safe: Microsoft

• Verify the exact build number of your Windows 10 or 11 installations.
• Compare your build numbers to the safe versions listed in the advisory.
• Apply the latest security updates as soon as they become available.
• Monitor network traffic for signs of unauthorized remote execution attempts.

Step-by-step guide: How Security Advisories Drive Patch Decisions and Reduce Risk

General security guidance from the Shell Bulletin newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is the CVSS score for CVE-2026-102210?

The National Vulnerability Database assigns a CVSS score of 9.8 to this vulnerability.

Which Windows 11 versions are affected?

Windows 11 Version 23H2 before build 10.0.22631.7652 and Version 24H2 before build 10.0.26100.9711 are affected.

Can an attacker exploit this flaw remotely?

Yes, the description states that an unauthorized attacker can execute code over a network.