CVE-2021-47480: scsi: core: Put LLD module refcnt after SCSI device is released

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-22 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: core: Put LLD module refcnt after SCSI device is released SCSI host release is triggered when SCSI device is freed. We have to make sure that the low-level device driver module won't be unloaded before SCSI host instance is released because shost->hostt is required in the release handler. Make sure to put LLD module refcnt after SCSI device is released. Fixes a kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi.

Affected products

Linux kernel: before 4.4.292; from 4.5 before 4.9.290; from 4.10 before 4.14.255; from 4.15 before 4.19.216; from 4.20 before 5.4.158; from 5.5 before 5.10.78 — fixed in 4.14.255, 4.19.216, 4.4.292, 4.9.290, 5.10.78, 5.14.17

How to fix

Upgrade to a fixed version: Linux kernel 4.14.255, 4.19.216, 4.4.292, 4.9.290. Check the vendor advisory for mitigations.

References

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