Advisory · CVE-2026-102210
Heap overflow in Windows Text Shaping allows network code execution
The Windows Text Shaping component has a heap-based buffer overflow an unauthenticated attacker can trigger over the network to execute code. Microsoft rates it CVSS 3.1 9.8.
- Vendor
- Microsoft
- Product
- Windows Text Shaping
- Identifier / CWE
- CVE-2026-102210
CWE-122 - Action timing
- Immediate
Explain it like I’m five
Software that draws letters on screen can be fed a malformed text payload that spills memory and turns into running code.
- 01Reach the component
An unauthenticated attacker sends crafted network traffic to a Windows system running Windows Text Shaping.
- 02Memory flaw triggers
The component mishandles the input and corrupts or reuses memory outside its intended bounds.
- 03Code runs
The attacker gains code execution in the component's context on the target system.
What happened
Microsoft disclosed CVE-2026-102210 in its October 2026 update guide: a heap-based buffer overflow (CWE-122) in Windows Text Shaping lets an unauthorized attacker execute code over a network on affected Windows and Windows Server releases.
Microsoft lists the affected Windows releases in its update guide. Apply the October 2026 security updates for your release rather than relying on a version guess here.
What to do
- Inventory every Windows Text Shaping deployment, including test, training, and individually managed instances.
- Apply the vendor fix or upgrade exactly as directed in the linked vendor bulletin or advisory.
- Restrict network access to Windows Text Shaping while remediation is underway, especially for internet-facing instances.
- Review application and server logs for application crashes while rendering text or documents, and malformed font or text payloads in received content.
- Check for accounts, content, or configuration created outside normal change processes, and rotate exposed credentials where access cannot be ruled out.
- Verify the deployed version or patch level after remediation.
Management note
Text rendering is everywhere, including servers that process documents nobody opened by hand. Patch broadly, not just on desktops.