CVE-2026-53183

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the Multipath TCP (MPTCP) implementation where the window field in the TCP header refers to the MPTCP-level rcv nxt. Because the TCP stack independently prevents the TCP-level receive window (rcv wnd) right edge from moving backward, the MPTCP receive window can become artificially inflated when incoming data is acknowledged at the TCP level but is out-of-order (OoO) in the MPTCP sequence space or resides in the backlog. This can lead to incoming traffic exceeding the receiver's rcvbuf size, even if the sender is operating correctly.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.