Microsoft Windows App: Information disclosure via out-of-bounds read in Remote Desktop Client
Summary
The Windows App (Remote Desktop client) contains an out-of-bounds read (CWE-125) that allows an unauthorized attacker to disclose information over the network. The attack requires a user to interact, for example by connecting to an attacker-controlled host via a malicious .rdp file or a link in a phishing message. The impact is limited to confidentiality; the attacker cannot execute code, but leaked memory may contain sensitive data.
Affected
- Windows App Client for Windows Desktop, versions 1.00 to before 2.0.1489.0
- Unknown: per-OS KB numbers and patched builds for Windows 10, Windows 11 and Windows Server
Fixed in
- Windows App Client for Windows Desktop 2.0.1489.0 or later
Workaround
- No patch-free workaround documented by the vendor.
- Interim control (recommendation, not a vendor statement): restrict which hosts users can connect to and limit outbound RDP connections from admin and staff devices.
Exploitation
- No evidence of exploitation in the wild found for this CVE.
- No public proof of concept found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact partial.
- Microsoft's exploitability fields for this CVE were not retrieved.
Our recommendation
- Update the Windows App to version 2.0.1489.0 or later.
- Check that all installed copies are updated, since OS updates may not cover a separately installed Windows App.
- Limit outbound RDP connections from admin and staff devices to trusted hosts.
- Warn users not to open unknown .rdp files or follow links that start remote desktop sessions.
- Check the MSRC advisory for the Microsoft score and per-OS KB list.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-121678 www.cve.org
- MSRC Security Update Guide CVE-2026-121678 msrc.microsoft.com
- Microsoft Windows App what's new learn.microsoft.com
- MSRC Security Update Guide CVE-2026-108419 (sister advisory) msrc.microsoft.com
- Cybersecurity News: multiple Windows Remote Desktop vulnerabilities cybersecuritynews.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 11 Nov 2026, 18:18.
Original description (NVD)
Out-of-bounds read in Remote Desktop Client allows an unauthorized attacker to disclose information 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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