CVE-2025-71220 in Linux
Summary
by MITRE • 02/14/2026
In the Linux kernel, the following vulnerability has been resolved:
smb/server: call ksmbd_session_rpc_close() on error path in create_smb2_pipe()
When ksmbd_iov_pin_rsp() fails, we should call ksmbd_session_rpc_close().
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Analysis
by VulDB Data Team • 05/06/2026
The vulnerability identified as CVE-2025-71220 resides within the Linux kernel's smb server implementation, specifically affecting the ksmbd subsystem that provides SMB/CIFS file sharing capabilities. This issue manifests in the create_smb2_pipe() function where proper cleanup procedures are not consistently executed during error conditions. The ksmbd subsystem serves as a critical component for enterprise file sharing and network access control, making this vulnerability particularly concerning for organizations relying on Linux-based file servers. The vulnerability represents a failure in resource management and error handling practices that could lead to system instability or resource exhaustion.
The technical flaw occurs when ksmbd_iov_pin_rsp() function fails during the execution of create_smb2_pipe(), which is responsible for creating SMB2 named pipes used for inter-process communication within the SMB protocol. The function call failure should trigger cleanup operations through ksmbd_session_rpc_close() to properly terminate RPC sessions and release associated resources. However, the current implementation fails to invoke this cleanup function when errors occur, leading to potential resource leaks and session state inconsistencies. This error path handling deficiency creates a scenario where system resources remain allocated even after error conditions have been detected, potentially leading to memory exhaustion or session corruption.
The operational impact of this vulnerability extends beyond simple resource leakage to encompass potential denial of service conditions and session management failures within SMB environments. When the ksmbd_session_rpc_close() function is not called on error paths, active RPC sessions may remain in inconsistent states, potentially causing subsequent operations to fail or behave unpredictably. Attackers could exploit this vulnerability by repeatedly triggering the error condition to accumulate resource leaks, eventually leading to system instability or service unavailability. The vulnerability affects systems running Linux kernels with ksmbd support, particularly those serving SMB/CIFS clients in enterprise environments where named pipe operations are frequently utilized for application communication and system services.
This vulnerability aligns with CWE-459, which describes "Incomplete Cleanup" in software implementations, and represents a classic example of improper error handling that violates fundamental security principles. From an ATT&CK perspective, this issue could be leveraged as part of a broader attack chain involving resource exhaustion techniques or service disruption. The lack of proper cleanup operations also creates potential opportunities for privilege escalation or information disclosure through resource state manipulation. Organizations should prioritize patching this vulnerability as it affects core system stability and could be exploited to compromise the availability and integrity of SMB services. The remediation approach requires ensuring that ksmbd_session_rpc_close() is consistently invoked whenever ksmbd_iov_pin_rsp() fails, establishing proper error path handling that maintains system integrity and resource availability.