UBUNTU-CVE-2026-89554

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix uninitialized localid in syncookie MPJOIN reconstruction mptcptokenjoincookieinitstate restores remotenonce, localnonce, backup, joinid, token and msk from the saved cookie entry when rebuilding the request socket for ...

CVE-2026-89554

CVE-2026-89554 affects the Linux kernel's MPTCP (Multipath TCP) implementation. When reconstructing a MP_JOIN request under SYN cookies, mptcp_token_join_cookie_init_state() fails to restore the local_id field from the saved cookie entry. Because the request-sock slab is SLAB_TYPESAFE_BY_RCU and ...