Microsoft Windows Remote Desktop Client: Remote code execution via use after free
Summary
A use-after-free flaw in the Remote Desktop Client component of Windows allows an unauthorized remote attacker to execute code on the affected system. Exploitation requires user interaction, for example opening a malicious connection or document, and high attack complexity. The main exposure is user workstations and endpoints, not internet-facing servers.
Affected
- Windows 10 Version 1607 and Windows Server 2016 (builds before 10.0.14393.9612)
- Windows 10 Version 1809 and Windows Server 2019 (builds before 10.0.17763.9376)
- Windows 10 Version 21H2 (builds before 10.0.19044.7807)
- Windows 10 Version 22H2 (builds before 10.0.19045.7807)
- Windows 11 Version 23H2 (builds before 10.0.22631.7652)
- Windows 11 Version 24H2 (builds before 10.0.26100.9711)
- Windows 11 Version 25H2 (builds before 10.0.26200.9711)
- Windows 11 Version 26H1 (builds before 10.0.28000.3231)
- Windows 11 Version 26H2 (builds before 10.0.26300.9711)
- Windows Server 2012 and 2012 R2 (builds before 6.2.9200.26434 and 6.3.9600.23470)
Fixed in
- Install the October 2026 Microsoft security update for the affected Windows version (fixed builds listed above, see MSRC advisory).
- KB number for Windows 10 1607: Unknown.
Workaround
- The CVE record provides no workaround.
- Generic aggregator advice: disable Remote Desktop on affected systems or restrict it to trusted networks until patched.
Exploitation
- CISA SSVC: exploitation none, not automatable, technical impact total.
- Not listed in CISA KEV.
- EPSS about 0.6%.
- No public proof of concept or in-the-wild exploitation found as of 2 Nov 2026.
Our recommendation
- Patch affected Windows 10, 11 and Server endpoints with the October 2026 update, together with the other Remote Desktop Client RCE fixes (CVE-2026-69995, CVE-2026-69996, CVE-2026-69997, CVE-2026-70004).
- Prioritise legacy Windows 10 1607 and 1809 systems and check whether they are still supported; an upgrade may be required.
- Restrict RDP to trusted networks until patched and do not expose RDP to the internet.
- Verify exact fixed builds and the KB number on the MSRC page before deployment.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Remote Desktop Client
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation unlikely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-69998 msrc.microsoft.com
- OpenCVE: CVE-2026-69998 app.opencve.io
- Vulners NVD record: CVE-2026-69998 vulners.com
- Strix: CVE-2026-69998 www.strix.ai
- SonicWall: Microsoft security bulletin coverage for October 2026 www.sonicwall.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 2 Nov 2026, 19:18.
Original description (NVD)
Use after free in Remote Desktop Client 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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