CVE-2026-62766 in Windows
Summary
by MITRE • 08/11/2026
Double free in Windows Kerberos allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability described represents a critical double free condition within the Windows Kerberos authentication system that enables authenticated attackers to achieve local privilege escalation. This flaw exists in the kerberos authentication service implementation where improper memory management routines allow a malicious user with valid credentials to manipulate heap allocation patterns and trigger duplicate memory deallocation scenarios. The technical exploitation involves crafting specific authentication requests that cause the kerberos service to free the same memory block twice, potentially leading to arbitrary code execution within the kernel context.
The underlying mechanism of this vulnerability stems from insufficient validation and memory handling within the kerberos ticket processing pipeline. When legitimate authentication requests are processed, the system fails to properly track memory allocations and deallocations, creating opportunities for attackers to manipulate the heap state through carefully constructed authentication sequences. This type of vulnerability falls under the CWE-415 category of double free conditions, which represents a fundamental memory management error that can be exploited to corrupt program execution flow.
From an operational perspective, this vulnerability poses significant risk to enterprise environments where kerberos is extensively used for authentication services. The requirement for prior authentication means that attackers must first obtain valid user credentials before attempting exploitation, but once achieved, the privilege escalation potential allows for complete system compromise. Attackers can leverage this weakness to elevate their privileges from standard user level to SYSTEM level access, effectively gaining full control over affected systems.
The attack vector typically involves an authenticated user session where the attacker crafts malicious kerberos requests that trigger the double free condition. This exploitation requires understanding of the kerberos protocol internals and memory management patterns within Windows operating systems. The vulnerability's impact extends beyond individual system compromise as it can be used as a foothold for broader network infiltration, particularly in environments where kerberos is used for cross-domain authentication and single sign-on services.
Security mitigations for this vulnerability include applying Microsoft security updates that address the specific memory management flaws within the kerberos implementation. Organizations should also implement monitoring solutions that detect anomalous authentication patterns and heap manipulation behaviors. Network segmentation strategies can help limit the potential impact of successful exploitation by reducing lateral movement capabilities. Additionally, implementing least privilege principles and regularly auditing authentication service configurations can minimize the attack surface for such vulnerabilities.
The exploitation of this double free condition aligns with several tactics described in the ATT&CK framework under privilege escalation techniques, specifically targeting the kerberos protocol as a means to achieve elevated system privileges. This vulnerability demonstrates how seemingly routine authentication services can contain critical memory safety issues that compromise entire system security postures when exploited by knowledgeable attackers.