Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Network-reachable RasMan service (AV:N), low complexity and no interaction, but requires an existing low-privileged account (PR:L); successful UAF yields full SYSTEM-level compromise, so C/I/A all High.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Use after free in Windows Remote Access Connection Manager allows an authorized attacker to elevate privileges over a network.
AnalysisAI
Privilege escalation in the Windows Remote Access Connection Manager (RasMan) service lets an authenticated, low-privileged attacker corrupt memory over the network to gain higher privileges on affected Windows 10, 11, and Server systems. The flaw is a CWE-416 use-after-free carrying a CVSS 8.8 with high impact to confidentiality, integrity, and availability. Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The Remote Access Connection Manager (RasMan) is a core Windows service that manages dial-up, VPN, and other remote-access connections, brokering RRAS/PPP connection state on behalf of clients. The root cause is CWE-416 (Use After Free): the service references a heap object after it has been freed, allowing an attacker who can influence the freed/reallocated memory to hijack execution flow or corrupt state within the service's privileged context. The CPE set confirms the affected component ships across the Windows client and server line - Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012 R2 through 2025, including Server Core installations - indicating a shared OS component rather than an add-on.
RemediationAI
Apply the Microsoft security update for CVE-2026-50666 (patch available per vendor advisory) via the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50666, prioritizing internet- or LAN-exposed hosts and any systems where low-privileged users have network access to the RasMan service; consult that page for the exact KB/build numbers for each OS version, as they were not included in the input data. Where patching must be staged, reduce exposure by disabling the Remote Access Connection Manager service (RasMan) on systems that do not use dial-up/VPN client connectivity - note this breaks VPN and remote-access client functionality and any dependent services - and restrict network access to the affected hosts from untrusted low-privilege accounts via host firewall and network segmentation. Do not rely on workarounds as a permanent fix; the vendor patch is the definitive remediation.
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Same weakness CWE-416 – Use After Free
View allSame technique Use After Free
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-44123
GHSA-6x6m-vhw2-wp6w