CVE-2024-41006 netrom: Fix a memory leak in nr_heartbeat_expiry()

What is CVE-2024-41006?

CVE-2024-41006 is a medium-severity denial of service vulnerability in Linux kernel, published on 12 Jul 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:

netrom: Fix a memory leak in nr_heartbeat_expiry()

syzbot reported a memory leak in nr_create() [0].

Commit 409db27e3a2e ("netrom: Fix use-after-free of a listening socket.") added sock_hold() to the nr_heartbeat_expiry() function, where a) a socket has a SOCK_DESTROY flag or b) a listening socket has a SOCK_DEAD flag.

But in the case "a," when the SOCK_DESTROY flag is set, the file descriptor has already been closed and the nr_release() function has been called. So it makes no sense to hold the reference count because no one will call another nr_destroy_socket() and put it as in the case "b."

nr_connect nr_establish_data_link nr_start_heartbeat

nr_release switch (nr->state) case NR_STATE_3 nr->state = NR_STATE_2 sock_set_flag(sk, SOCK_DESTROY);

nr_rx_frame nr_process_rx_frame switch (nr->state) case NR_STATE_2 nr_state2_machine() nr_disconnect() nr_sk(sk)->state = NR_STATE_0 sock_set_flag(sk, SOCK_DEAD)

nr_heartbeat_expiry switch (nr->state) case NR_STATE_0 if (sock_flag(sk, SOCK_DESTROY) || (sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) sock_hold() // ( !!! ) nr_destroy_socket()

To fix the memory leak, let's call sock_hold() only for a listening socket.

Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org) with Syzkaller.

[0]: https://syzkaller.appspot.com/bug?extid=d327a1f3b12e1e206c16

Weakness: CWE-401

Which versions are affected by CVE-2024-41006?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-41006?

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-2024-41006 being exploited?

There is no known exploitation of CVE-2024-41006 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 BELL-CVE-2024-41006, DEBIAN-CVE-2024-41006, GHSA-xp5x-wr7x-fp9j, UBUNTU-CVE-2024-41006.