{"id":"AZL-94026","summary":"CVE-2026-64541 affecting package kernel for versions less than 6.6.145.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket\n\nsmc_cdc_rx_handler() looks up the connection by token under the link\ngroup's conns_lock, drops the lock, and then dereferences conn and the\nsmc_sock derived from it, ending in sock_hold(&smc-\u003esk) inside\nsmc_cdc_msg_recv(). No reference is held across the lock release.\n\nThe only reference pinning the socket while the connection is\ndiscoverable in the link group is taken in smc_lgr_register_conn()\n(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both\nunder conns_lock. Once the handler drops conns_lock, a concurrent\nclose() -\u003e smc_release() -\u003e smc_conn_free() -\u003e smc_lgr_unregister_conn()\ncan drop that reference and free the smc_sock, so the handler's later\nsock_hold() runs on freed memory:\n\n  WARNING: lib/refcount.c:25 at refcount_warn_saturate\n  Workqueue: rxe_wq do_work\n   refcount_warn_saturate (lib/refcount.c:25)\n   smc_cdc_msg_recv (net/smc/smc_cdc.c:430)\n   smc_cdc_rx_handler (net/smc/smc_cdc.c:502)\n   smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)\n   tasklet_action_common (kernel/softirq.c:938)\n   handle_softirqs (kernel/softirq.c:622)\n  Kernel panic - not syncing: panic_on_warn set\n\nOnly SMC-R is affected. The SMC-D receive tasklet is stopped by\ntasklet_kill(&conn-\u003erx_tsklet) in smc_conn_free() before the connection\nis unregistered, so it cannot run concurrently with the free.\n\nTake the socket reference while still holding conns_lock, so the\nregistration reference can no longer be the last one, and drop it once\nthe handler is done.","modified":"2026-08-28T17:47:46.451351612Z","published":"2026-07-27T21:17:06Z","upstream":["CVE-2026-64541"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64541"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.145.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-94026.json"}}],"schema_version":"1.9.0"}