CVE-2022-48909 net/smc: fix connection leak

What is CVE-2022-48909?

CVE-2022-48909 is a medium-severity denial of service vulnerability in Linux kernel, published on 22 Aug 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:

net/smc: fix connection leak

There's a potential leak issue under following execution sequence :

smc_release smc_connect_work if (sk->sk_state == SMC_INIT) send_clc_confirim tcp_abort(); ... sk.sk_state = SMC_ACTIVE smc_close_active switch(sk->sk_state) { ... case SMC_ACTIVE: smc_close_final() // then wait peer closed

Unfortunately, tcp_abort() may discard CLC CONFIRM messages that are still in the tcp send buffer, in which case our connection token cannot be delivered to the server side, which means that we cannot get a passive close message at all. Therefore, it is impossible for the to be disconnected at all.

This patch tries a very simple way to avoid this issue, once the state has changed to SMC_ACTIVE after tcp_abort(), we can actively abort the smc connection, considering that the state is SMC_INIT before tcp_abort(), abandoning the complete disconnection process should not cause too much problem.

In fact, this problem may exist as long as the CLC CONFIRM message is not received by the server. Whether a timer should be added after smc_close_final() needs to be discussed in the future. But even so, this patch provides a faster release for connection in above case, it should also be valuable.

Weakness: CWE-401

Which versions are affected by CVE-2022-48909?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-48909?

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-2022-48909 being exploited?

There is no known exploitation of CVE-2022-48909 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 DEBIAN-CVE-2022-48909, GHSA-q2w7-x8j6-5gxc, UBUNTU-CVE-2022-48909.