{"id":"AZL-88899","summary":"CVE-2026-46227 affecting package kernel for versions less than 6.6.141.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL\n\nThe SCTP_SENDALL path in sctp_sendmsg() iterates ep-\u003easocs with\nlist_for_each_entry_safe(), which caches the next entry in @tmp before\nthe loop body runs.  The body calls sctp_sendmsg_to_asoc(), which may\ndrop the socket lock inside sctp_wait_for_sndbuf().\n\nWhile the lock is dropped, another thread can SCTP_SOCKOPT_PEELOFF the\nassociation cached in @tmp, migrating it to a new endpoint via\nsctp_sock_migrate() (list_del_init() + list_add_tail() to\nnewep-\u003easocs), and optionally close the new socket which frees the\nassociation via kfree_rcu().  The cached @tmp can also be freed by a\nnetwork ABORT for that association, processed in softirq while the\nlock is dropped.\n\nsctp_wait_for_sndbuf() revalidates @asoc (the current entry) on re-lock\nvia the \"sk != asoc-\u003ebase.sk\" and \"asoc-\u003ebase.dead\" checks, but nothing\nrevalidates @tmp.  After a successful return, the iterator advances to\nthe stale @tmp, yielding either a use-after-free (if the peeled socket\nwas closed) or a list-walk onto the new endpoint's list head (type\nconfusion of &newep-\u003easocs as a struct sctp_association *).\n\nBoth are reachable from CapEff=0; the type-confusion path gives\ncontrolled indirect call via the outqueue.sched-\u003einit_sid pointer.\n\nFix by re-deriving @tmp from @asoc after sctp_sendmsg_to_asoc()\nreturns.  @asoc is known to still be on ep-\u003easocs at that point: the\nonly callers that list_del an association from ep-\u003easocs are\nsctp_association_free() (which sets asoc-\u003ebase.dead) and\nsctp_assoc_migrate() (which changes asoc-\u003ebase.sk), and\nsctp_wait_for_sndbuf() checks both under the lock before any\nsuccessful return; a tripped check propagates as err \u003c 0 and the loop\nbails before the re-derive.\n\nThe SCTP_ABORT path in sctp_sendmsg_check_sflags() returns 0 and the\nloop hits 'continue' before sctp_sendmsg_to_asoc() is ever called, so\nthe @tmp cached by list_for_each_entry_safe() still covers the\nlock-held free that ba59fb027307 (\"sctp: walk the list of asoc\nsafely\") was added for.","modified":"2026-08-28T17:47:52.970365580Z","published":"2026-05-28T10:16:38Z","upstream":["CVE-2026-46227"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46227"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.141.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-88899.json"}}],"schema_version":"1.9.0"}