CVE-2026-63867

Updated on 19 Jul 2026

Severity

8.2 High severity

Details

CVSS score
8.2

Overview

About vulnerability

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

mptcp: close TOCTOU race while computing rcv_wnd

The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv wnd for the same packet.

Refactor the cote to avoid inconsistencies which may confuse the peer. Also ensure that the MPTCP level rcv wnd is updated only when the egress packet actually contains a DSS ack.

Details

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Amazon Linux 2023 Planned
Debian 12 Planned