Bug 2420263 (CVE-2022-50640)

Summary: CVE-2022-50640 kernel: mmc: core: Fix kernel panic when remove non-standard SDIO card
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw in the Linux kernel mmc core driver was discovered that could lead to a kernel panic and memory corruption when a non-standard SDIO card is removed. The Vulnerability arises because SDIO tuples are only allocated for standard SDIO cards, resulting in an inconsistent reference count for the device structure. When the non-standard card is removed, the reference counter is decremented without the corresponding earlier increment, potentially triggering use of freed memory or panic conditions. A local user with access to the affected subsystem could trigger this behavior, causing the kernel to crash.
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Description OSIDB Bzimport 2025-12-09 01:04:12 UTC 
In the Linux kernel, the following vulnerability has been resolved:

mmc: core: Fix kernel panic when remove non-standard SDIO card

SDIO tuple is only allocated for standard SDIO card, especially it causes
memory corruption issues when the non-standard SDIO card has removed, which
is because the card device's reference counter does not increase for it at
sdio_init_func(), but all SDIO card device reference counter gets decreased
at sdio_release_func().
Comment 1 Alexander B 2025-12-10 06:19:50 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120935-CVE-2022-50640-324c@gregkh/T