mptcp: allow subflow rcv wnd to shrink

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UBUNTU-CVE-2026-53183

In the Linux kernel, the following vulnerability has been resolved: mptcp: allow subflow rcv wnd to shrink In MPTCP connection, the window field in the TCP header refers to the MPTCP-level rcvnxt and it's right edge should not move backward. Such constraint is enforced at DSS option generation...

CVE-2026-53183 mptcp: allow subflow rcv wnd to shrink

In the Linux kernel, the following vulnerability has been resolved: mptcp: allow subflow rcv wnd to shrink In MPTCP connection, the window field in the TCP header refers to the MPTCP-level rcvnxt and it's right edge should not move backward. Such constraint is enforced at DSS option generation...

CVE-2026-53183

CVE-2026-53183 affects the Linux kernel MPTCP implementation. The issue allows the TCP subflow receive window to shrink independently of the netns, which can inflate the MPTCP receive window and cause incoming data to exceed the receiver’s rcvbuf, potentially leading to DoS or a system becoming u...