Description

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

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-08-11T17:18:35.457Z",
  "pubdate": "2026-08-11T17:18:35.457Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within the Reliable Multicast Transport Driver (RMCAST), allowing an unauthorized threat actor to execute arbitrary code over an adjacent network. This critical flaw exposes affected systems to remote code execution risks without requiring user interaction or prior authentication.\nThe vulnerability resides in the core packet processing logic of the RMCAST driver, which fails to properly validate the size parameters of incoming multicast packets before copying data into dynamically allocated heap memory buffers. An attacker possessing positioning on the same adjacent network segment can transmit a specially crafted sequence of malicious packets designed to exhaust the bounds of the target memory buffer.\nSuccessful exploitation of this memory corruption flaw results in heap metadata corruption and potentially arbitrary code execution with kernel-level or high-privileged system permissions, depending on the operational context of the driver. This introduces catastrophic risk implications, including complete system compromise, denial of service through kernel panics or blue screens, and lateral movement facilitation across the local network segment. Mitigation requires applying official vendor patches or disabling the vulnerable Reliable Multicast Transport Driver component where feasible.",
  "technicalDetails": "The vulnerability is classified as a heap-based buffer overflow occurring within the Reliable Multicast Transport Driver (RMCAST). The root cause stems from insufficient bounds checking and improper validation of packet length attributes supplied in network headers prior to executing memory copy operations.\nSpecifically, when the RMCAST driver processes incoming network traffic, it allocates a buffer on the heap to store payload data. Due to the absence of rigorous length validation against the actual allocated chunk size, a maliciously crafted packet containing an oversized length field forces the memory copy routine to write past the boundaries of the destination heap buffer.\nThe attack vector requires the adversary to have adjacency to the target network, enabling the transmission of malicious multicast packets directly to the vulnerable interface managed by RMCAST. Because the driver operates at a low networking layer and processes packets asynchronously, no user authentication or interaction is required to trigger the vulnerable code path.\nThe step-by-step attack flow proceeds as follows: First, the attacker crafts a specialized RMCAST packet featuring a manipulated length descriptor that exceeds the allocated heap buffer size. Second, the attacker transmits this payload onto the adjacent network segment. Third, the RMCAST driver receives the packet and passes it to the vulnerable parsing function. Fourth, the driver allocates a heap buffer and initiates a memory copy operation using the untrusted length value. Fifth, the overflow condition corrupts adjacent heap chunks, control structures, or function pointers.\nPost-exploitation impact includes the potential redirection of execution flow through heap exploitation techniques. Because RMCAST components typically execute with elevated privileges within the operating system kernel, successful payload execution grants the attacker absolute control over the underlying system, facilitating persistent access, credential theft, and further compromise of network assets."
}