CVE-2024-47809 dlm: fix possible lkb_resource null dereference

What is CVE-2024-47809?

CVE-2024-47809 is a medium-severity vulnerability in Linux kernel, published on 11 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-476

Which versions are affected by CVE-2024-47809?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-47809?

Apply the vendor's patch.

Is CVE-2024-47809 being exploited?

There is no known exploitation of CVE-2024-47809 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-56121, AZL-56166, BELL-CVE-2024-47809, DEBIAN-CVE-2024-47809, GHSA-9fhm-w5m6-rqv5, ROOT-OS-DEBIAN-11-CVE-2024-47809 and 3 more.