CVE-2026-96300 in Windows
Summary
by MITRE • 10/14/2026
Uncontrolled resource consumption in RPC Endpoint Mapper Service allows an unauthorized attacker to deny service over a network.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves a flaw within the Remote Procedure Call (RPC) Endpoint Mapper Service, specifically categorized as uncontrolled resource consumption. This type of weakness typically falls under CWE-400, which covers situations where a software process does not properly control the allocation and maintenance of limited resources, leading to exhaustion or depletion. In this specific context, the RPC Endpoint Mapper is responsible for managing connections between clients and servers by mapping requested services to their corresponding endpoints. An attacker who can interact with this service over a network without proper authentication may exploit this flaw to trigger excessive resource usage on the target system.
The technical mechanism behind this denial of service attack likely involves sending specially crafted requests that force the Endpoint Mapper Service to allocate disproportionate amounts of memory, CPU cycles, or thread handles for each connection attempt. Because the service is designed to handle a high volume of incoming mapping requests from various clients, it may lack sufficient validation or rate-limiting mechanisms when processing these inputs. By repeatedly initiating connections or sending malformed packets that require significant computational overhead to parse and respond to, an attacker can rapidly deplete system resources. This exhaustion prevents legitimate users and services from accessing the RPC infrastructure, effectively rendering the host machine unresponsive for network-based remote procedure calls.
From a strategic perspective, this vulnerability aligns with MITRE ATT&CK technique T1499, Endpoint Denial of Service, which describes methods used to disrupt access to an endpoint or its resources. The impact is severe as it compromises the availability component of the CIA triad for any system relying on RPC services for inter-process communication or remote administration. In enterprise environments where RPC is critical for Active Directory replication, file sharing, and other distributed operations, such a denial of service can halt business continuity and disrupt network-wide functionality. The attacker does not need to gain persistent access or exfiltrate data; the mere ability to crash or slow down the target system constitutes a successful exploitation of this vulnerability.
Mitigation strategies for this issue primarily involve applying vendor-supplied security patches that address the resource handling logic within the RPC Endpoint Mapper Service. Organizations should ensure their systems are updated with the latest cumulative updates from Microsoft, as these often include fixes for known denial-of-service vectors in core system services. Additionally, network-level controls can be implemented to restrict access to the RPC endpoints. This includes configuring firewalls to limit inbound traffic on ports associated with the Endpoint Mapper, typically port 135, and ensuring that only authorized IP addresses or subnets are permitted to communicate with these services. Implementing strict input validation at the gateway level can also help filter out malformed requests before they reach the vulnerable service component.