EUVD-2026-73799
GHSA-rwwm-fwvq-xf47
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Kernel UAF via network packet; AC:H for race condition; S:C because ring-0 code execution transcends the RMCAST driver's security boundary to the full OS.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Use after free in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over a network.
AnalysisAI
Use-after-free in the Windows Reliable Multicast Transport Driver (rmcast.sys) enables unauthenticated remote code execution across all supported Windows versions from Server 2012 to Server 2025 and Windows 10/11. An attacker sending crafted multicast packets over the network can trigger the CWE-416 condition in the kernel-mode driver, leading to corrupted memory that yields arbitrary code execution at kernel privilege. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The Windows Message Queuing (MSMQ) feature must be installed and active - rmcast.sys only loads when MSMQ is present. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H scores 8.1 and signals a remotely triggerable, unauthenticated kernel UAF, but high attack complexity (AC:H) reflects an inherent race condition that limits one-shot reliability. … 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 distributed through Windows Update or WSUS that brings each affected build to or above the patched build numbers listed in EUVD-2026-73799 (e.g., Windows Server 2025 to 10.0.26100.33438, Windows 11 24H2 to 10.0.26100.9445, Windows Server 2022 to 10.0.20348.5622). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all systems running Windows Server 2012-2025 and Windows 10/11 using your asset inventory and CMDB. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today