Windows App: Information disclosure via out-of-bounds read in Remote Desktop Client
Summary
The Windows App client, which provides access to Azure Virtual Desktop, Windows 365 and remote PCs, contains an out-of-bounds read in its Remote Desktop Client component. An attacker can disclose information from client memory over the network without authentication. Exploitation requires that a user connects to an attacker-controlled or spoofed RDP host. Only confidentiality is affected; integrity and availability are not.
Affected
- Windows App Client for Windows Desktop from 1.00 before 2.0.1489.0
Fixed in
- 2.0.1489.0 (implied by the CVE.org record and sibling entry CVE-2026-108419; not yet confirmed on the MSRC page for this CVE)
- Newest build found in public listings: 2.0.1485.0 (November 1, 2026); 2.0.1489.0 not yet publicly listed
Workaround
Unknown.
- Connect only to known, trusted RDP hosts until the client is updated
Exploitation
- No evidence of exploitation in the wild (CISA SSVC: exploitation none; KEV: no)
- No public proof of concept found
- EPSS 0.00868 (low predicted likelihood)
Our recommendation
- Update Windows App to 2.0.1489.0 or later through your update tooling, and verify the build in the Microsoft Store or winget
- Check the MSRC advisory for the final list of fixed components
- Restrict RDP connections to known internal or Azure hosts and warn staff about connecting to unknown hosts
- Treat as medium priority; keep the Windows App current
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE.org record CVE-2026-121677 www.cve.org
- MSRC Security Update Guide CVE-2026-121677 msrc.microsoft.com
- MSRC Security Update Guide CVE-2026-108419 (sibling entry) msrc.microsoft.com
- Strix.ai CVE-2026-121677 www.strix.ai
- VULNERS EUVD-2026-99475 (EPSS) vulners.com
- Stack.watch Microsoft Remote Desktop stack.watch
- TechSpot Windows App www.techspot.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, 12:04.
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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