CVE-2023-54085: mptcp: fix NULL pointer dereference on fastopen early fallback

Published Dec 24, 2025
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

mptcp: fix NULL pointer dereference on fastopen early fallback

In case of early fallback to TCP, subflowsynrecvsock() deletes the subflow context before returning the newly allocated sock to the caller.

The fastopen path does not cope with the above unconditionally dereferencing the subflow context.

Affected Software

1 affected component
linux_kernel

Event History

Dec 24, 2025
CVE Published
via MITRE·01:06 PM
Data Sourced
via MITRE·01:06 PM
DescriptionSeverity
Data Sourced
via NVD·01:16 PM
DescriptionSeverity
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Frequently Asked Questions

1

What is the severity of CVE-2023-54085?

CVE-2023-54085 is considered a medium severity vulnerability in the Linux kernel.

2

How do I fix CVE-2023-54085?

To resolve CVE-2023-54085, update the Linux kernel to the latest version that includes the fix.

3

What is the impact of CVE-2023-54085?

CVE-2023-54085 can lead to a NULL pointer dereference during an early fallback to TCP, potentially causing system instability.

4

Which versions of Linux kernel are affected by CVE-2023-54085?

CVE-2023-54085 affects multiple versions of the Linux kernel prior to the patch being applied.

5

What is the nature of CVE-2023-54085?

CVE-2023-54085 is a vulnerability related to mptcp that occurs during processing in subflow_syn_recv_sock.

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