CVE-2023-53427: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53427 is a vulnerability in the Linux kernel's CIFS (Common Internet File System) implementation, specifically affecting the RDMA (Remote Direct Memory Access) functionality. The vulnerability was discovered and disclosed on September 18, 2025, affecting the Linux kernel's CIFS subsystem. The issue occurs when handling Memory Region (MR) allocation failures in the SMB3 RDMA implementation (Red Hat CVE).

The vulnerability stems from improper initialization of MR recovery work and list clearing when MR allocation fails in the CIFS implementation. This leads to a Use-After-Free (UAF) condition when destroying the MR list. The vulnerability has been assigned a CVSS v3.1 base score of 4.1 (AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H), indicating a local attack vector with high attack complexity and requiring high privileges (Red Hat XML).

The primary impact of this vulnerability is a potential kernel crash leading to denial of service on the affected system. The vulnerability affects client-side operations and can result in system instability when mounting CIFS shares using RDMA. Confidentiality and integrity of the system are not expected to be compromised (Red Hat XML).

Red Hat has acknowledged the vulnerability and its status varies across different versions: Red Hat Enterprise Linux 6 and 7 are not affected, while versions 8 and 9 (including kernel-rt variants) have deferred fixes. The fix involves initializing the MR recovery work before MR allocation to prevent the warning and removing MRs from the list to prevent the UAF condition (Red Hat XML).