Microsoft Windows Remote Desktop Services: Remote code execution via use after free
Summary
A use-after-free memory corruption flaw in Windows Remote Desktop Services (the server side of RDP) allows an attacker to execute code over the network. According to the CVSS vector, the attack complexity is high and user interaction is required, which lowers the likelihood of exploitation. The impact is rated high for confidentiality, integrity and availability.
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 and 25H2, Windows 11 26H1 and 26H2 (fixed build numbers to be verified, see notes)
- Windows Server 2012 and 2012 R2 (builds before 6.2.9200.26434 and 6.3.9600.23470)
- Unknown: exact fixed builds for Windows 11 24H2 and Windows 11 26H2 are conflicting in sources.
Fixed in
- Install the October 2026 security updates from Microsoft.
- Windows 10 21H2/22H2: KB5126657 (per Tenable).
- Windows 10 1809 / Server 2019: KB5126651; Windows Server 2025: KB5126646.
- Windows 10 1607 / Server 2016: KB number unknown, confirm with Microsoft.
- Verify exact fixed builds in the MSRC advisory before relying on them.
Workaround
- Vendor-aligned guidance: disable Remote Desktop Services if not essential and remove the RDP feature (not confirmed on MSRC).
- Do not expose TCP 3389 to the internet.
- Place RDP behind a VPN or gateway and enforce multi-factor authentication.
- These measures reduce exposure but do not fix the flaw.
Exploitation
- Not listed in CISA KEV as of the latest check.
- EPSS about 0.6% (0.00631).
- VulDB estimates a possible exploit market price of USD 25k-100k; this is not evidence of exploitation.
- No public proof-of-concept found in our searches, which is not a confirmation of absence.
- No confirmed in-the-wild exploitation known as of 2 Nov 2026.
- CISA SSVC: exploitation none, not automatable, total technical impact.
Our recommendation
- Identify all Windows hosts with Remote Desktop Services enabled, including standalone Windows 10 1607 and Server 2016 systems.
- Check which systems are reachable from the internet and patch them first.
- Install the October 2026 updates and confirm the installed build against the fixed builds.
- Restrict RDP access to VPN or gateway, enforce MFA, and monitor RDP logs for unusual activity.
- Disable RDS on systems where it is not required.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Windows Remote Desktop Services
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- 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
- MSRC Security Update Guide msrc.microsoft.com
- NVD mirror (Vulners) vulners.com
- Tenable plugin 365467 www.tenable.com
- OpenCVE app.opencve.io
- VulDB 418298 vuldb.com
- Strix CVE-2026-69992 www.strix.ai
- Vulners EPSS record vulners.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, 19:14.
Original description (NVD)
Use after free in Windows Remote Desktop Services 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.
Affected? We can help.
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