CVE-2026-103569 in Windows
Summary
by MITRE • 10/13/2026
Out-of-bounds read in Windows IKE Extension allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified as an out-of-bounds read within the Internet Key Exchange (IKE) extension of Microsoft Windows represents a critical memory safety flaw that can be exploited by remote attackers to achieve arbitrary code execution or sensitive data disclosure. The IKE protocol is fundamental to establishing secure, authenticated communications channels using cryptographic keys in virtual private networks and other network security contexts. When processing incoming packets from untrusted sources, the vulnerable component fails to adequately validate buffer boundaries before reading memory contents. This lack of rigorous input validation allows an attacker who sends a specially crafted packet over the network to trigger a read operation that accesses memory locations outside the intended allocation. Such out-of-bounds reads typically result in the disclosure of internal kernel or system state information, which can include cryptographic keys, authentication tokens, or other sensitive data residing in adjacent memory regions.
From a technical perspective, this flaw aligns with CWE-125, Out-of-bounds Read, and is often associated with improper input validation mechanisms that fail to check array indices or buffer lengths against allocated sizes. In the context of network-facing services like IKE, which operates over UDP port 500 and ESP ports, the attack surface is significantly expanded because it accepts traffic from external networks without requiring prior authentication in certain phases of the negotiation process. An attacker positioned on a reachable network segment can exploit this condition by crafting malformed IKE packets that cause the system to read beyond the allocated buffer boundaries. The consequences extend beyond mere information leakage; depending on how the leaked data is utilized, an attacker may gain insights into memory layout for further exploitation or bypass security controls designed to protect sensitive communications.
The operational impact of this vulnerability is severe due to its potential for remote code execution and privilege escalation if combined with other techniques such as heap spraying or use-after-free scenarios that might arise from subsequent handling of corrupted data structures. Even in isolation, the ability to disclose arbitrary memory contents undermines the confidentiality guarantees provided by IKE itself, potentially allowing adversaries to decrypt previously captured traffic or impersonate legitimate peers after obtaining sufficient cryptographic material. This directly impacts organizations relying on Windows-based infrastructure for secure remote access and site-to-site VPN connections, exposing them to espionage, data exfiltration, and lateral movement within their networks.
Mitigation strategies must prioritize immediate patching through official Microsoft security updates that address the underlying memory management errors in the IKE extension. Administrators should ensure all affected systems are updated with the latest cumulative patches released by Microsoft for Windows operating systems. In environments where patching is not immediately feasible, network segmentation and firewall rules restricting access to UDP port 500 and associated ESP protocols from untrusted networks can reduce exposure. Additionally, deploying intrusion detection or prevention systems capable of identifying malformed IKE packets may provide an additional layer of defense against exploitation attempts while longer-term architectural improvements are implemented to enforce stricter input validation across all network protocol handlers.