CVE-2022-50846
Unknown Unknown - Not Provided

Null Pointer Dereference in Linux mmc_add_host() Causes Kernel Crash

Publication date: 2025-12-30

Last updated on: 2025-12-30

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: mmc: via-sdmmc: fix return value check of mmc_add_host() mmc_add_host() may return error, if we ignore its return value, it will lead two issues: 1. The memory that allocated in mmc_alloc_host() is leaked. 2. In the remove() path, mmc_remove_host() will be called to delete device, but it's not added yet, it will lead a kernel crash because of null-ptr-deref in device_del(). Fix this by checking the return value and goto error path which will call mmc_free_host().

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Meta Information

Published
2025-12-30
Last Modified
2025-12-30
Generated
2026-07-06
AI Q&A
2025-12-30
EPSS Evaluated
2026-07-05
NVD
CVE-2022-50846
EUVD
EUVD-2022-55852

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability occurs in the Linux kernel's mmc subsystem, specifically in the via-sdmmc driver. The function mmc_add_host() may return an error, but if its return value is ignored, two problems arise: first, memory allocated by mmc_alloc_host() is leaked; second, during device removal, mmc_remove_host() is called on a device that was never successfully added, causing a kernel crash due to a null pointer dereference in device_del(). The fix involves properly checking the return value of mmc_add_host() and handling errors by freeing allocated memory.

Impact Analysis

This vulnerability can lead to memory leaks and kernel crashes on affected Linux systems using the via-sdmmc driver. The kernel crash caused by a null pointer dereference can result in system instability or denial of service, potentially disrupting normal operations.

Mitigation Strategies

To mitigate this vulnerability, update the Linux kernel to a version where the mmc: via-sdmmc driver includes the fix for checking the return value of mmc_add_host(). This prevents memory leaks and kernel crashes caused by null pointer dereferences. Until the update is applied, avoid using affected MMC devices if possible.

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