CVE-2026-58594 is a Remote Desktop Client Remote Code Execution vulnerability caused by an integer overflow or wraparound issue. Microsoft rates it as CVSS v3.1 base 8.8 and temporal 7.7, with a NETWORK attack vector, LOW attack complexity, NO privileges required, and REQUIRED user interaction. The impact is high across confidentiality, integrity, and availability. Microsoft reports no public disclosure and no known exploitation, with exploit code maturity UNPROVEN. Because it requires user interaction but can be reached over the network and allows remote code execution, it is relevant for enterprise environments where users may open attacker-controlled remote desktop content or connections.

Highlights:
- CVSS scores: Base 8.8 - Temporal 7.7
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN
- Impact: Remote Code Execution with HIGH confidentiality, integrity, and availability impacts
- Exploitation likelihood: Exploitation Less Likely; network vector with LOW attack complexity, NO privileges required, and REQUIRED user interaction
- Severity for enterprise: High severity due to remote code execution and network reachability, but risk is reduced relative to fully unauthenticated/no-interaction remote issues because user interaction is required
- Patch status: available; customer action required

Affected systems:
- Windows 10 1607, 1809, 21H2, 22H2
- Windows 11 24H2, 25H2, 26H1, unspecified
- Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025