CVE-2024-40931 mptcp: ensure snd_una is properly initialized on connect

What is CVE-2024-40931?

CVE-2024-40931 is a medium-severity 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:

mptcp: ensure snd_una is properly initialized on connect

This is strictly related to commit fb7a0d334894 ("mptcp: ensure snd_nxt is properly initialized on connect"). It turns out that syzkaller can trigger the retransmit after fallback and before processing any other incoming packet - so that snd_una is still left uninitialized.

Address the issue explicitly initializing snd_una together with snd_nxt and write_seq.

Weakness: CWE-908

Which versions are affected by CVE-2024-40931?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-40931?

Apply the vendor's patch.

Is CVE-2024-40931 being exploited?

There is no known exploitation of CVE-2024-40931 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-2024-40931, DEBIAN-CVE-2024-40931, GHSA-c6gv-gfxc-vrwh, UBUNTU-CVE-2024-40931.