CVE-2026-97811 in Windows
Summary
by MITRE • 10/15/2026
Double free in OpenSSH for Windows allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified as a double free error within the OpenSSH implementation for Microsoft Windows represents a critical memory management flaw that can be exploited by authenticated users to achieve local privilege escalation. This type of defect typically arises when software incorrectly handles deallocation of dynamically allocated memory, specifically by attempting to release a pointer that has already been freed or is no longer valid. In the context of OpenSSH for Windows, which operates with elevated system privileges to facilitate secure remote access and tunneling services, such an error in the core authentication or session management logic provides a direct pathway for attackers to manipulate process memory structures during runtime operations.
From a technical perspective, double free vulnerabilities are particularly dangerous because they allow an attacker to corrupt heap metadata or overwrite adjacent memory regions with controlled data. When the application attempts to free the same memory block twice, it may trigger undefined behavior that can be leveraged to execute arbitrary code within the context of the running OpenSSH daemon process. Since this service typically runs under a high-privilege account such as SYSTEM or Administrator on Windows systems, successful exploitation results in the attacker gaining full control over the host machine without requiring additional authentication steps beyond initial access to the SSH service.
The operational impact of this vulnerability is severe, effectively bypassing the intended security boundaries of the operating system. An authorized attacker who has valid credentials for an account with limited privileges can exploit this flaw during a legitimate SSH session or through automated scripts that interact with the OpenSSH server. By carefully crafting malicious input that triggers the double free condition, the attacker can gain administrative rights on the compromised host. This capability undermines the principle of least privilege and allows for further lateral movement within a network, installation of persistent backdoors, exfiltration of sensitive data, or disruption of critical services running under elevated privileges.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-415, which defines double free as a condition where memory is freed more than once, leading to heap corruption and potential code execution. Furthermore, in the context of the MITRE ATT&CK framework, this exploitation technique falls under Tactic TA0004: Privilege Escalation, specifically mapping to techniques such as Exploitation for Privilege Escalation (T1068) or potentially leveraging specific OS vulnerabilities like Windows Local Security Authority Subsystem Service (LSASS) memory corruption if the attack vector targets those components. The lack of proper bounds checking and state validation in the memory management routines is a fundamental design flaw that violates secure coding standards regarding resource lifecycle management.
Mitigation strategies must prioritize immediate patching through official vendor updates provided by Microsoft or the OpenSSH maintainers, as these releases typically include corrected memory handling logic and enhanced input validation mechanisms. Until patches are applied, organizations should restrict network access to the SSH service using strict firewall rules, ensuring that only trusted IP addresses can connect. Additionally, implementing multi-factor authentication adds a layer of defense against unauthorized access attempts, although it does not directly prevent exploitation by already authenticated users. Regular auditing of system logs for anomalous process behavior and memory usage patterns can also aid in early detection of attempted exploits. Security teams should verify the integrity of installed binaries using cryptographic hashes to ensure no tampering has occurred prior to applying fixes.