CVE-2026-62816: Windows Reliable Multicast Transport Driver (RMCAST) Remote Code Execution Vulnerability

Heap-based buffer overflow in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over an adjacent network.

CSIRTS triage

What: Heap-based buffer overflow in RMCAST allows remote code execution over an adjacent network without authentication.
Who is affected: Unauthorized remote attackers on adjacent networks where RMCAST is enabled.
Urgency: Critical (CVSS 8.8) with unauthenticated remote exploitation; immediate patching required.
Action: Apply Windows security update addressing CVE-2026-62816 and restrict multicast traffic if possible.

AI-assisted analysis generated from the source advisory — verify against the original.

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EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-628160.39% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 33% of all EPSS-scored CVEs.

CVE	CSIRTS overview	External
CVE-2026-62816	coverage & exploitation status	NVD · CVE.org

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