CVE-2022-50834

Vulnerability

Description

CVE-2022-50834 addresses a resource leak in the Linux kernel's NFC (Near Field Communication) subsystem. The function nfc_get_device() takes an additional reference on a device, but in certain code paths that reference was not released with a corresponding nfc_put_device() call, potentially leading to reference count leaks and dangling device objects [1][2][3].

Exploitation

Exploitation requires that an attacker trigger code paths in the NFC subsystem where nfc_get_device() is called without the matching nfc_put_device(). In the absence of proper cleanup, the device reference count remains elevated, causing the device to never be freed. While there is no direct mechanism for arbitrary code execution, a local attacker with access to NFC interfaces could cause a denial-of-service condition by exhausting kernel memory through repeated reference leaks.

Impact

The primary impact is a denial of service due to memory exhaustion. An unprivileged local user could cause the kernel to leak small amounts of memory each time the vulnerable code path is triggered. Over time, this could lead to system instability or a complete denial of service. No privilege escalation or remote exploitation is indicated.

Mitigation

The fix was included in the Linux kernel stable releases with commits [1][2][3]. Administrators should apply the latest stable kernel updates to ensure the missing nfc_put_device() calls are added. There is no workaround other than applying the patch or disabling the NFC subsystem if not needed.