CVE-2024-40931

MEDIUM
Published Jul 12, 2024 Modified Nov 3, 2025 CWE-908

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.

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-908 CWE-908

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/208cd22ef5e57f82d38ec11c1a1703f9401d6dde https://git.kernel.org/stable/c/7b9c7fc8600b64a86e4b47b2d190bba380267726 https://git.kernel.org/stable/c/8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 https://git.kernel.org/stable/c/ef473bf1dd7e8dd08bcc04b9e2d1bfed69a0a7ce https://git.kernel.org/stable/c/f03c46eabb3a67bd2993e237ab5517f00a5f1813 https://git.kernel.org/stable/c/f1f0a46f8bb8890b90ab7194f0a0c8fe2a3fb57f https://git.kernel.org/stable/c/208cd22ef5e57f82d38ec11c1a1703f9401d6dde https://git.kernel.org/stable/c/7b9c7fc8600b64a86e4b47b2d190bba380267726 https://git.kernel.org/stable/c/8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 https://git.kernel.org/stable/c/ef473bf1dd7e8dd08bcc04b9e2d1bfed69a0a7ce https://git.kernel.org/stable/c/f03c46eabb3a67bd2993e237ab5517f00a5f1813 https://git.kernel.org/stable/c/f1f0a46f8bb8890b90ab7194f0a0c8fe2a3fb57f

Frequently Asked Questions

What is CVE-2024-40931? +
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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2024-40931? +
CVE-2024-40931 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2024-40931? +
CVE-2024-40931 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-40931? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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