Windows Remote Desktop Services: Elevation of privilege via double free
Summary
A double free vulnerability in Windows Remote Desktop Services allows an authorized local attacker to elevate privileges. The attacker needs a local, low-privileged account and must win a race condition. The flaw is not reachable from the internet, but multi-user RDS session hosts and terminal servers are at greatest risk.
Affected
- Windows Server 2016 and Server Core installation: 10.0.14393.0 before 10.0.14393.9688
- Windows Server 2019 and Server Core installation: 10.0.17763.0 before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 before 10.0.20348.5870
- Windows Server 2025 and Server Core installation: 10.0.26100.0 before 10.0.26100.33822
- Windows client editions: Unknown.
Fixed in
- Security updates released by Microsoft on November 10, 2026, per edition (see MSRC advisory).
- Fixed builds are the upper boundary of each affected range; inferred from the vendor's wording, not stated separately.
- KB article numbers: Unknown.
Workaround
Unknown.
Exploitation
- No public exploit or proof of concept found.
- No evidence of in-the-wild exploitation.
- CISA SSVC: exploitation none, not automatable, total technical impact.
- Exploitation requires local, low-privileged access and a race condition.
Our recommendation
- Install the November 2026 cumulative update on all affected servers, starting with multi-user RDS session hosts, terminal servers and shared servers.
- Include Hyper-V hosts that run RDS-enabled guests, since the flaw can reportedly be triggered from inside a guest VM.
- Restrict local logon on RDS session hosts to users who need it.
- Check the MSRC advisory for client-edition coverage and any mitigation text.
- Monitor for unusual local privilege changes and re-check exploitation status after patch release.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Critical
- Impact
- Elevation of privilege – 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)
- KB5131291, KB5131085, KB5131090, KB5131080, KB5131077
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide (MSRC) msrc.microsoft.com
- CVE Record (CVE.org) www.cve.org
- VulDB vuldb.com
- Action1 Patch Tuesday November 2026 www.action1.com
- Talos Patch Tuesday November 2026 blog.talosintelligence.com
- Strix CVE mirror www.strix.ai
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 11 Nov 2026, 03:36.
Original description (NVD)
Double free in Windows Remote Desktop Services allows an authorized attacker to elevate privileges locally.
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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