CVE-2022-50729: 
Linux Debian vulnerability analysis and mitigation

CVE-2022-50729 is a resource leak vulnerability in the Linux kernel's ksmbd (kernel SMB daemon) subsystem, specifically in the ksmbd_session_rpc_open() function. When ksmbd_rpc_open() fails, the code does not call ksmbd_rpc_id_free() to release the resource allocated by ksmbd_ipc_id_alloc(), resulting in a resource leak. The vulnerability was published on December 24, 2025, and affects Linux kernel versions starting from commit e2f34481b24d up to the respective fix commits across stable branches. It carries an estimated CVSS severity of Medium, with an EPSS score of approximately 0.018% (Feedly, EUVD).

The root cause is a missing cleanup path in ksmbd_session_rpc_open() within the Linux kernel's ksmbd module (CWE-401: Missing Release of Memory after Effective Lifetime / resource leak). When ksmbd_rpc_open() returns a failure, the IPC ID previously allocated via ksmbd_ipc_id_alloc() is not freed via ksmbd_rpc_id_free(), leaving the resource unreleased. The fix was applied across multiple stable kernel branches via commits 31c1b5d3000c, 9cb49b95c05d, f9ed133381eb, and bc044414fa03 (Feedly, EUVD).

The primary impact of this vulnerability is resource exhaustion within the ksmbd subsystem of the Linux kernel. Repeated triggering of the failure path in ksmbd_session_rpc_open() could cause IPC IDs to be leaked, potentially degrading SMB server performance or stability over time. This is an availability concern rather than a confidentiality or integrity issue, and there is no known path to privilege escalation or data exfiltration from this vulnerability alone (Feedly).

There is no known public exploit code, active in-the-wild exploitation, or threat actor attribution associated with CVE-2022-50729. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. It was detected by Nessus plugin 280059 (Feedly, Tenable).

The fix has been backported to multiple Linux stable kernel branches. Patched versions include Linux 5.15.86, 6.0.16, 6.1.2, and 6.2 (mainline). Administrators should update to a kernel version that includes one of the fix commits: 31c1b5d3000c, 9cb49b95c05d, f9ed133381eb, or bc044414fa03. As a workaround, disabling the ksmbd module (if SMB kernel-level serving is not required) would eliminate exposure to this code path (EUVD, Feedly).