{"id":"CVE-2026-89478","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89478","summary":"sctp: drop a chunk if its transport was removed","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: drop a chunk if its transport was removed\n\nsctp_rcv() resolves the transport once per packet and leaves it in\nchunk->transport. The lookup reference, or the one sctp_add_backlog() takes\nif the socket is owned by userspace, keeps it around until the chunk has\nbeen processed.\n\nAn authenticated ASCONF DEL-IP can remove it in the meantime.\nsctp_assoc_rm_peer() takes the transport out of the association and calls\nsctp_transport_free(), which tags it dead and drops the reference the\nassociation held. There is a window on both paths: the packet can sit on\nthe socket backlog, and on the direct path the lookup completes before\nbh_lock_sock().\n\nThe DATA chunk in that packet puts the removed transport back into\nasoc->peer.last_data_from. Once the packet is done that reference goes\naway and the transport is freed by RCU, so the next delayed SACK carries\nthe pointer into the SACK chunk and sctp_outq_select_transport() reads the\nfreed transport's state.\n\nDrop the chunk in sctp_inq_push(), next to the existing rcvr->dead check.\nBoth paths reach it with the association's socket lock held. The peer\nretransmits it.","published":"2026-09-11T19:43:34.588Z","modified":"2026-09-14T03:46:07.042482467Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/03a9d10ecf71f54b2af8020935f2033d4a132be5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1035bdef1efb9b1076d1a57b81e08c637ff08ecc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3537961df2163258bddc230db0e18dc14e925ea6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c6c86a5e62a4fec36692ddd64b9144b660f71f96"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89478.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89478"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:07.042482467Z"}}