CVE-2026-69597 in Windows
Summary
by MITRE • 09/08/2026
Use after free in Windows HTTP.sys allows an authorized attacker to elevate privileges over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described involves a use-after-free condition within the Windows HTTP Server API driver, commonly referred to as http.sys. This component is responsible for handling Hypertext Transfer Protocol requests on Microsoft Windows operating systems and serves as a critical infrastructure element for web services running on affected platforms. The flaw arises from improper memory management practices where the system fails to properly nullify pointers after freeing allocated memory blocks or allows access to memory that has already been deallocated by another process or thread. This specific type of error is categorized under CWE-416, which defines use-after-free as a class of software vulnerabilities resulting from dangling pointer usage. When an attacker triggers this condition, they can manipulate the state of the kernel-mode driver in ways that were not intended by its design, leading to arbitrary code execution capabilities within the context of the operating system's most privileged account.
From an operational perspective, the impact of this vulnerability is severe because it allows for privilege escalation over a network without requiring prior authentication on many configurations or with minimal credentials depending on the specific service exposure. An authorized attacker who has access to the vulnerable HTTP endpoint can craft maliciously formatted HTTP requests that exploit the memory corruption flaw. By carefully controlling the contents and timing of these requests, the attacker can overwrite critical data structures in kernel memory, effectively gaining control over the execution flow of the operating system. This capability transforms a remote network interaction into a full compromise of the underlying host machine, granting the attacker SYSTEM-level privileges which provide unrestricted access to all files, processes, and security settings on the compromised server.
The exploitation vector aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to initial execution and privilege escalation via kernel exploits. Attackers often leverage such vulnerabilities as part of a broader campaign where an initially low-privileged account is used to gain foothold before escalating rights to maintain persistence or move laterally across a network. The presence of this flaw in http.sys highlights the risks associated with complex, high-performance drivers that handle large volumes of traffic and must manage dynamic memory allocation under varying loads. These conditions increase the likelihood of race conditions or logic errors that lead to dangling pointers if not rigorously tested during development cycles.
Mitigation strategies primarily involve applying vendor-supplied security patches that address the underlying memory management issues within the http.sys driver. Organizations should prioritize updating all internet-facing servers and internal web services running affected versions of Windows to ensure these vulnerabilities are remediated. Additionally, implementing network segmentation can help limit exposure by restricting access to HTTP endpoints only from trusted subnets or specific IP ranges. Deploying intrusion detection systems that monitor for anomalous HTTP traffic patterns associated with exploitation attempts provides an additional layer of defense in depth. Regular vulnerability scanning and penetration testing focused on web server configurations further assist in identifying misconfigurations that might expose these services unnecessarily, thereby reducing the attack surface available to potential adversaries seeking to exploit memory corruption flaws for privilege escalation.