CVE-2026-102203 in Windows
Summary
by MITRE • 10/13/2026
Access of resource using incompatible type ('type confusion') in RPC Runtime allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability described constitutes a critical security flaw within the Remote Procedure Call (RPC) runtime environment, specifically categorized as a type confusion error. This class of defect arises when software incorrectly assumes that a data structure or variable is of one specific type while it actually contains another, leading to unpredictable behavior during execution. In the context of RPC systems, which are fundamental for inter-process communication and distributed computing across networks, such an inconsistency can be exploited by malicious actors to bypass standard security controls. The core technical issue lies in the improper validation or casting of data types received from remote clients, allowing an attacker to manipulate internal pointers or memory structures that were not intended to accept their input format.
From a technical perspective, this type confusion typically manifests when the RPC runtime processes incoming requests without sufficiently verifying the integrity and expected schema of the payload. If the system fails to enforce strict typing constraints during deserialization or method invocation, an attacker can craft a specially formatted request that tricks the runtime into interpreting data as executable code or valid memory addresses rather than simple parameters. This misinterpretation enables the overwriting of critical control flow data on the heap or stack, such as function pointers or return addresses. By carefully crafting these inputs, an unauthorized user can redirect the execution path of the vulnerable process to arbitrary locations in memory where they have placed shellcode or other malicious payloads.
The operational impact of this vulnerability is severe due to its network-accessible nature and potential for remote code execution. Since RPC services often run with elevated privileges to facilitate system administration tasks, successful exploitation grants an attacker full control over the affected host. This can lead to a complete compromise of confidentiality, integrity, and availability. Attackers may use this foothold to install backdoors, exfiltrate sensitive data, pivot to other systems within the network, or establish persistent access. The ability to execute code remotely without authentication makes this particularly dangerous in enterprise environments where RPC services are frequently exposed on internal networks for legitimate administrative purposes but lack sufficient perimeter defenses against sophisticated exploitation attempts.
This vulnerability aligns with Common Weakness Enumeration (CWE) ID 843, which defines Access of Resource Using Incompatible Type, and is closely related to CWE-120 Buffer Overflow if the type confusion leads to out-of-bounds writes. Furthermore, in terms of tactical mapping within the MITRE ATT&CK framework, this exploit technique corresponds to Tactic TA0004 Privilege Escalation or TA0005 Defense Evasion depending on how it is leveraged, and specifically relates to techniques involving memory corruption such as T1203 Exploitation for Client Execution. The lack of proper input validation represents a fundamental failure in secure coding practices that allows external actors to influence internal program logic through malformed data structures.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Organizations should immediately apply vendor-provided patches or updates that address the specific type checking deficiencies within the RPC runtime library. If patching is not feasible, network-level controls such as firewalls can be configured to restrict access to RPC ports exclusively from trusted IP addresses, thereby reducing the attack surface. Additionally, implementing strict input validation and sanitization routines in any custom applications interacting with the RPC service can help prevent malformed data from reaching vulnerable components. Developers should also adopt secure coding standards that emphasize rigorous type checking and bounds verification during deserialization processes to eliminate similar vulnerabilities at their source.