Windows: Heap-based buffer overflow in Text Shaping allows remote code execution
Summary
A heap-based buffer overflow in the Windows Text Shaping component allows an unauthorized attacker to execute code over a network. The vulnerability is rated CVSS 9.8 (critical), and according to the CVSS vector no authentication or user interaction is required. The attack surface is not identified in the sources, so exposure depends on which service processes untrusted input that reaches text rendering.
Affected
- Windows 10 Version 1607 and Windows Server 2016: builds 10.0.14393.0 up to 10.0.14393.9612 (exclusive)
- Windows 10 Version 1809: builds 10.0.17763.0 up to 10.0.17763.9376 (exclusive)
- Windows 10 Version 21H2: builds 10.0.19044.0 up to 10.0.19044.7807 (exclusive)
- Windows 10 Version 22H2: build range listed inconsistently in the sources; verify on the MSRC page
- Windows 11 Version 23H2: builds 10.0.22631.0 up to 10.0.22631.7652 (exclusive)
- Windows 11 Version 24H2: builds 10.0.26100.0 up to 10.0.26100.9711 (exclusive)
- Windows 11 Version 25H2: builds 10.0.26200.0 up to 10.0.26200.9711 (exclusive)
- Windows 11 Version 26H1: builds 10.0.28000.0 up to 10.0.28000.3231 (exclusive)
- Windows 11 Version 26H2: builds 10.0.26300.0 up to 10.0.26300.9711 (exclusive)
- Windows Server 2012 (incl. Server Core): builds 6.2.9200.0 up to 6.2.9200.26434 (exclusive)
- Windows Server 2012 R2 (incl. Server Core): builds 6.3.9600.0 up to 6.3.9600.23470 (exclusive)
Fixed in
- Install the October 2026 security update from Microsoft (published 13 Oct 2026) for your Windows version.
- Fixed builds: Windows 10 1607 and Server 2016 10.0.14393.9612; Windows 10 1809 10.0.17763.9376; Windows 10 21H2 10.0.19044.7807; Windows 11 23H2 10.0.22631.7652; Windows 11 24H2, 25H2 and 26H2 10.0.26100.9711, 10.0.26200.9711 and 10.0.26300.9711; Windows 11 26H1 10.0.28000.3231.
- KB numbers: Unknown. See the MSRC page.
Workaround
Unknown. No Microsoft-specific mitigation was identified. Apply the security update.
Exploitation
- Exploitation in the wild: not confirmed for this CVE.
- Public proof of concept: unknown.
Our recommendation
- Patch Windows 10 1607, Windows Server 2016 and other affected systems first.
- Check the Microsoft lifecycle page for the support status of Windows 10 1607 and plan an upgrade if it is out of support.
- Inventory affected systems and identify services that accept network input and reach text rendering.
- Limit inbound network exposure of unpatched systems and isolate those that cannot be patched from untrusted networks.
- Monitor for abnormal process activity on affected hosts.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Critical
- Impact
- Remote code execution – Windows Text Shaping
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126835, KB5126836, KB5126868, KB5126651, KB5126653, KB5127648
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-97814 msrc.microsoft.com
- CVE record aggregator: CVE-2026-97814 cve.threatint.com
- Action1: Patch Tuesday October 2026 www.action1.com
- CrowdStrike: Patch Tuesday analysis October 2026 www.crowdstrike.com
- Cisco Talos: Microsoft Patch Tuesday for October 2026 blog.talosintelligence.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 18:11.
Original description (NVD)
Heap-based buffer overflow in Windows Text Shaping allows an unauthorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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