CVE-2026-97568

In the Linux kernel, the following vulnerability has been resolved: mptcp: syncookies: remember the request backup flag Instead of using an uninitialised bit when copying the info in subflow_ulp_clone(). To fix this, no need to extend the join_entry structure: backup is coming from struct mptcp_subflow_request_sock, only one bit. Do the same here by using one bit for both.

• https://git.kernel.org/stable/c/00b2bd518911e0daab00f4749cce68c191ccebb4
• https://git.kernel.org/stable/c/06d649f9cd03a9f8e768a658b20acf8d2c8022e0
• https://git.kernel.org/stable/c/61178d0b85b4b1b53e78b06e89d018d22d102f88
• https://git.kernel.org/stable/c/b76c0e28b392620dfbaf92cdeedbf115820b44cb