CVE-2024-56729 smb: Initialize cfid->tcon before performing network ops

What is CVE-2024-56729?

CVE-2024-56729 is a medium-severity denial of service vulnerability in Linux kernel, published on 29 Dec 2024. 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:

smb: Initialize cfid->tcon before performing network ops

Avoid leaking a tcon ref when a lease break races with opening the cached directory. Processing the leak break might take a reference to the tcon in cached_dir_lease_break() and then fail to release the ref in cached_dir_offload_close, since cfid->tcon is still NULL.

Weakness: CWE-401

Which versions are affected by CVE-2024-56729?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-56729?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2024-56729 being exploited?

There is no known exploitation of CVE-2024-56729 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-54999, BELL-CVE-2024-56729, DEBIAN-CVE-2024-56729, GHSA-rcmj-jxvj-g49v, ROOT-OS-DEBIAN-12-CVE-2024-56729, UBUNTU-CVE-2024-56729.