CVE-2026-68820 in Windows
Summary
by MITRE • 08/12/2026
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability represents a critical use-after-free condition within the Windows Ancillary Function Driver for WinSock component that enables local privilege escalation when exploited by an authenticated attacker. The flaw occurs in the way the system handles memory management during socket operations, specifically when processing certain ancillary data structures that are passed between user-mode applications and kernel-mode drivers. The vulnerability stems from improper validation of input parameters and lack of proper synchronization mechanisms when multiple threads access shared memory regions. When a malicious user-level process triggers specific socket operations with crafted ancillary data, the driver fails to properly validate or sanitize these inputs before accessing previously freed memory locations, creating opportunities for arbitrary code execution in kernel context. The technical implementation involves the driver's failure to maintain proper reference counting mechanisms and object lifecycle management during asynchronous socket operations, which allows attackers to manipulate memory layout and potentially overwrite critical kernel structures.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the target system through kernel-level access. Once successfully exploited, the attacker can bypass standard security controls including user access tokens, process isolation mechanisms, and even anti-virus software that operates at user level since the exploitation occurs within kernel space. The attack vector requires local authentication but does not need network connectivity, making it particularly dangerous in environments where users have legitimate access to systems. According to CWE classification, this vulnerability maps to CWE-416 Use After Free which is categorized under the broader weakness of improper lifetime management of resources. The ATT&CK framework would classify this as privilege escalation through kernel exploits with techniques such as privilege escalation via kernel exploitation and persistence mechanisms that leverage system-level access.
Mitigation strategies should focus on immediate patch deployment from Microsoft security updates, which typically address the underlying memory management flaws in the WinSock driver implementation. System administrators should implement least privilege principles by restricting user accounts to minimal required permissions and monitoring for unusual socket operations or memory access patterns that might indicate exploitation attempts. Network segmentation and endpoint detection solutions can help identify anomalous behavior related to kernel-level memory access patterns, though traditional antivirus solutions may be ineffective against kernel-level exploits. Organizations should also consider implementing exploit prevention technologies such as control flow integrity checks and address space layout randomization to make successful exploitation more difficult. The vulnerability highlights the importance of proper input validation and resource management in kernel-mode drivers, emphasizing that even authorized users with legitimate access can pose significant threats when operating within systems that contain memory safety flaws. Regular security assessments of system components should include thorough analysis of driver behavior and memory management practices to identify similar vulnerabilities before they can be exploited by malicious actors.