CVE-2023-53751 in Linux
Summary
by MITRE • 12/08/2025
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix potential use-after-free bugs in TCP_Server_Info::hostname
TCP_Server_Info::hostname may be updated once or many times during reconnect, so protect its access outside reconnect path as well and then prevent any potential use-after-free bugs.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/23/2026
The vulnerability identified as CVE-2023-53751 resides within the Linux kernel's CIFS (Common Internet File System) implementation, specifically targeting the TCP_Server_Info::hostname member variable. This issue manifests as a potential use-after-free bug that can occur during network reconnection scenarios, representing a critical security concern for systems relying on CIFS file sharing protocols. The vulnerability is particularly significant because it affects the fundamental network communication infrastructure that many enterprise and enterprise-grade systems depend upon for file access and sharing operations.
The technical flaw stems from improper synchronization and access control of the hostname member variable within the TCP_Server_Info structure. During reconnect operations, the hostname field undergoes multiple updates, but the protection mechanisms only safeguard access within the reconnect path itself. This design oversight creates a race condition where external code paths can access the hostname member while it is being modified or freed, leading to potential use-after-free conditions. The vulnerability demonstrates a classic improper synchronization pattern that violates fundamental memory safety principles and can result in arbitrary code execution or system crashes.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable remote code execution attacks. When exploited, the use-after-free condition could allow an attacker to manipulate memory contents or cause privilege escalation, particularly in environments where CIFS servers are accessible to untrusted networks. The vulnerability affects systems running Linux kernels that implement CIFS client functionality, making it relevant across various server and desktop environments that utilize network file sharing. Organizations with extensive CIFS infrastructure, including enterprise file servers, cloud storage solutions, and distributed computing environments, face heightened risk from this flaw.
Mitigation strategies for CVE-2023-53751 involve applying the kernel patches that implement proper synchronization mechanisms around the TCP_Server_Info::hostname access. The fix requires protecting hostname access not only within the reconnect path but also in all external code paths that may interact with this member variable during network reconnection events. System administrators should prioritize updating their Linux kernel versions to include the patched implementations, particularly in production environments where CIFS services are actively used. Additionally, monitoring network traffic for unusual reconnection patterns and implementing network segmentation can provide additional layers of protection while patches are deployed. This vulnerability aligns with CWE-416, which addresses use-after-free conditions, and could potentially map to ATT&CK technique T1059 for command and control communications through compromised CIFS services. Organizations should also consider implementing intrusion detection systems to monitor for potential exploitation attempts targeting this specific memory corruption vulnerability.