{"id":"DEBIAN-CVE-2026-64541","details":"In the Linux kernel, the following vulnerability has been resolved:  net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket  smc_cdc_rx_handler() looks up the connection by token under the link group's conns_lock, drops the lock, and then dereferences conn and the smc_sock derived from it, ending in sock_hold(&smc-\u003esk) inside smc_cdc_msg_recv(). No reference is held across the lock release.  The only reference pinning the socket while the connection is discoverable in the link group is taken in smc_lgr_register_conn() (sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both under conns_lock. Once the handler drops conns_lock, a concurrent close() -\u003e smc_release() -\u003e smc_conn_free() -\u003e smc_lgr_unregister_conn() can drop that reference and free the smc_sock, so the handler's later sock_hold() runs on freed memory:    WARNING: lib/refcount.c:25 at refcount_warn_saturate   Workqueue: rxe_wq do_work    refcount_warn_saturate (lib/refcount.c:25)    smc_cdc_msg_recv (net/smc/smc_cdc.c:430)    smc_cdc_rx_handler (net/smc/smc_cdc.c:502)    smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445)    tasklet_action_common (kernel/softirq.c:938)    handle_softirqs (kernel/softirq.c:622)   Kernel panic - not syncing: panic_on_warn set  Only SMC-R is affected. The SMC-D receive tasklet is stopped by tasklet_kill(&conn-\u003erx_tsklet) in smc_conn_free() before the connection is unregistered, so it cannot run concurrently with the free.  Take the socket reference while still holding conns_lock, so the registration reference can no longer be the last one, and drop it once the handler is done.","modified":"2026-09-01T16:06:56.457541984Z","published":"2026-07-27T21:17:06.570Z","upstream":["CVE-2026-64541"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-64541"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.180-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not 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