CVE-2025-22042 in Linux
Summary
by MITRE • 04/16/2025
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: add bounds check for create lease context
Add missing bounds check for create lease context.
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Analysis
by VulDB Data Team • 02/15/2026
The vulnerability identified as CVE-2025-22042 resides within the Linux kernel's ksmbd subsystem, which provides SMB/CIFS file sharing capabilities for Linux systems. This subsystem enables Linux servers to communicate with SMB clients using the Server Message Block protocol, commonly employed in enterprise environments for file sharing and network access. The ksmbd implementation serves as a bridge between Linux file systems and Windows-based network clients, facilitating seamless integration in mixed operating system environments.
The technical flaw manifests as a missing bounds check within the create lease context processing logic of the ksmbd subsystem. When a client initiates an SMB transaction requesting a lease creation, the server must validate the incoming data structure to ensure it conforms to expected parameters and size limitations. Without proper bounds checking, malicious or malformed input data could cause the kernel to access memory locations beyond the allocated buffer boundaries, potentially leading to memory corruption and arbitrary code execution. This vulnerability specifically affects the validation of lease context data structures that are part of the SMB protocol negotiation process.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a critical security weakness that could be exploited by remote attackers to gain unauthorized access to affected systems. When exploited, the missing bounds check could allow an attacker to manipulate the kernel's memory layout through carefully crafted SMB requests, potentially leading to privilege escalation or system compromise. The vulnerability affects systems running Linux kernels with ksmbd support enabled, particularly those serving SMB/CIFS shares in enterprise environments where network exposure is high. Attackers could leverage this weakness to execute arbitrary code with kernel-level privileges, bypassing standard user-space security controls.
Mitigation strategies for CVE-2025-22042 should prioritize immediate kernel updates from trusted sources, as the vulnerability has been resolved through proper bounds checking implementation. System administrators should conduct thorough inventory assessments to identify all systems running ksmbd services and ensure timely patch deployment across all affected environments. Network segmentation and access control measures can provide additional defense-in-depth layers, limiting exposure of SMB services to trusted networks only. Monitoring for suspicious SMB traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The fix aligns with established security practices outlined in the CWE taxonomy under CWE-129 Input Validation and the ATT&CK framework's privilege escalation techniques, demonstrating the importance of proper input validation in kernel-space operations. Organizations should also consider implementing automated patch management solutions to ensure rapid deployment of security updates across their infrastructure.