CVE-2026-70208 in Windows
Summary
by MITRE • 10/14/2026
Out-of-bounds read in Windows HTTP.sys allows an authorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a critical out-of-bounds read flaw within the Hypertext Transfer Protocol (HTTP) service driver, commonly referred to as http.sys, which is a core component of Microsoft Windows operating systems responsible for handling incoming HTTP requests and managing connections between clients and web services. This specific defect allows an authorized attacker with local access on the target system to exploit improper memory boundary checks during the processing of specially crafted network packets or internal API calls directed at the service. When http.sys processes these malformed inputs, it fails to validate that the requested data length does not exceed the allocated buffer size, leading to a read operation that accesses memory locations beyond the intended boundaries. This behavior constitutes an out-of-bounds read vulnerability, which is categorized under CWE-125 in the Common Weakness Enumeration standard as an Out-of-Bounds Read condition where software reads data past the end or before the beginning of the intended buffer.
The operational impact of this flaw centers on information disclosure rather than direct code execution or privilege escalation, although such disclosures can serve as a precursor to more severe attacks. By triggering this out-of-bounds read, an attacker can cause the system to leak sensitive kernel-mode memory contents into user-space accessible buffers or response headers. This leaked data may contain cryptographic keys, session tokens, stack pointers, or other confidential information that was previously stored in adjacent memory regions. The ability to exfiltrate such internal state significantly compromises the confidentiality of the host and potentially the broader network if shared credentials or encryption material are exposed. From a threat modeling perspective, this activity aligns with ATT&CK technique T1005, which describes Data from Local System as an initial access vector where adversaries gather data directly from local sources to support further exploitation phases such as lateral movement or persistence establishment.
Mitigation strategies for this vulnerability primarily involve the immediate application of security patches provided by Microsoft that address the boundary validation logic within http.sys. Administrators should ensure that all systems running affected versions of Windows are updated with the latest cumulative updates, which typically include fixes for known memory safety issues in core networking components. In environments where patching is not immediately feasible due to operational constraints, network segmentation and strict access controls can help mitigate risk by limiting local user privileges and restricting direct interaction with HTTP endpoints that might be targeted. Additionally, deploying endpoint detection and response solutions capable of monitoring abnormal memory access patterns or unexpected data exfiltration attempts can provide early warning indicators for exploitation activities targeting this specific flaw in the http.sys driver architecture.