EUVD-2026-73892
GHSA-jv5h-625j-qxjp
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Network-reachable kernel driver with no auth required, but use-after-free race condition demands high attack complexity; full kernel compromise justifies C:H/I:H/A:H.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
4DescriptionCVE.org
Use after free in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over a network.
AnalysisAI
Remote code execution is possible across Windows Server 2019, 2022, and 2025 as well as Windows 10 Version 1809 through a use-after-free vulnerability (CWE-416) in the Reliable Multicast Transport Driver (rmcast.sys), a kernel-mode component. An unauthenticated network attacker can exploit a race condition in the driver to corrupt freed kernel memory and achieve arbitrary code execution at SYSTEM privilege level. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The target system must have the Reliable Multicast Transport (RMCAST/PGM) Windows networking feature explicitly installed, which loads rmcast.sys - this is an optional component and is not enabled by default on all Windows installations; it requires deliberate installation through Windows Features or DISM. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 8.1 vector (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects a network-reachable, unauthenticated path to full kernel compromise, but the AC:H metric is the critical moderating factor: reliable exploitation demands winning a race condition window that requires precise timing and repeated attempts, a meaningful technical barrier compared to trivially exploitable bugs. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply the Microsoft security update corresponding to your Windows build: upgrade Windows Server 2025 and Server Core to build 10.0.26100.33438 or later, Windows Server 2022 to 10.0.20348.5622 or later, and Windows Server 2019 plus Windows 10 Version 1809 to 10.0.17763.9245 or later through Windows Update, WSUS, or Microsoft Update Catalog. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify and inventory all Windows Server 2019, 2022, 2025 and Windows 10 1809+ systems; prioritize servers in network-facing roles and domain controllers for urgent patching. …
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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
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