CVE-2026-50509 is a Wireless Wide Area Network Service (WwanSvc) elevation of privilege vulnerability caused by deserialization of untrusted data. Microsoft rates it High severity with a CVSS v3.1 base score of 7.8 and temporal score of 6.8. The vector is local, low complexity, requires low privileges, and no user interaction. If successfully exploited, an attacker could gain SYSTEM privileges, with high confidentiality, integrity, and availability impact. Microsoft lists exploitation likelihood as “Exploitation More Likely,” but there are no public disclosures or known exploitation reports, and exploit code maturity is unproven. Because the attack is local rather than network-based, enterprise risk is concentrated on systems where an attacker already has local access or can execute code.

Highlights:
- CVSS scores: Base 7.8 - Temporal 6.8
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN
- Impact: Elevation of Privilege; confidentiality HIGH, integrity HIGH, availability HIGH
- Exploitation likelihood: Exploitation More Likely; vector is LOCAL, with LOW attack complexity, LOW privileges required, and NO user interaction
- Severity for enterprise: High severity, but lower exposure than network-reachable vulnerabilities because exploitation is local-only; highest concern is for endpoints or servers where untrusted local code or users may be present
- Patch status: available; customer action required

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