{"id":"CVE-2026-98253","summary":"RDMA/ucma: Serialize join and leave on copy_to_user failure","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/ucma: Serialize join and leave on copy_to_user failure\n\nrdma_join_multicast() queues RoCE work that later reads the ucma_multicast\nthrough event-\u003eparam.ud.private_data, then list_add()s the CMA multicast\nat the head of id_priv-\u003emc_list. rdma_leave_multicast() matches only by\nsockaddr and destroys the first hit.\n\nucma_process_join() used to drop ctx-\u003emutex after a successful join and\nretake it only if copy_to_user() failed. Two concurrent JOIN_MCAST calls\nwith the same address can therefore insert a second CMA entry before the\nfirst thread's leave. leave then cancels the newer work and the older\nworker still dereferences the ucma_multicast that the first thread frees.\n\nKeep ctx-\u003emutex held from rdma_join_multicast() through copy_to_user() and,\non -EFAULT, through rdma_leave_multicast() so leave cannot miss this join.\nDo not leave if join itself failed: that path never published this address\non mc_list, and a leave-by-addr would destroy an earlier successful join.","modified":"2026-10-08T02:52:55.903805995Z","published":"2026-10-06T08:45:20.077Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98253.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/01cbdb724c584d7772fd25af2e4dfdf8527ce0d5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/01e29d0d78a8f66f221625720a04939eef5ec1f6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/43c4e24bd10370fc976f6220518049ce71419399"},{"type":"WEB","url":"https://git.kernel.org/stable/c/52172e11bd074ccaded21740ffeb67123f01dd00"},{"type":"WEB","url":"https://git.kernel.org/stable/c/662ade4de9ff5eceb0820a9f8e9fac70ba6a815b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/83610ee5e498fa5bfcb80031d2b959baea276bf6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ae805d204cf1f15b87d1bf3529b4c649f3519420"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98253.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98253"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"60d613b39e8d0c9f3b526e9c96445422b4562d76"},{"fixed":"29b9ed83d8bfab5c6e11fcbf1aa836aa4ae26cb9"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fe454dc31e84f8c14cb8942fcb61666c9f40745b"},{"fixed":"52172e11bd074ccaded21740ffeb67123f01dd00"},{"fixed":"01e29d0d78a8f66f221625720a04939eef5ec1f6"},{"fixed":"ae805d204cf1f15b87d1bf3529b4c649f3519420"},{"fixed":"43c4e24bd10370fc976f6220518049ce71419399"},{"fixed":"01cbdb724c584d7772fd25af2e4dfdf8527ce0d5"},{"fixed":"83610ee5e498fa5bfcb80031d2b959baea276bf6"},{"fixed":"662ade4de9ff5eceb0820a9f8e9fac70ba6a815b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.10.20"},{"fixed":"5.10.271"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.11.3"},{"fixed":"5.12"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a3262b3884dd67b4c5632ce7cdf9cff9d1a575d4"}]}],"versions":["v5.10.270","v5.10.269","v5.10.268","v5.10.267","v5.10.266","v5.10.265","v5.10.264","v5.10.263","v5.10.262","v5.10.261","v5.10.260","v5.10.259","v5.10.258","v5.10.257","v5.10.256","v5.10.255","v5.10.254","v5.10.253","v5.10.252","v5.10.251","v5.10.250","v5.10.249","v5.10.248","v5.10.247","v5.10.246","v5.10.245","v5.10.244","v5.10.243","v5.10.242","v5.10.241","v5.10.240","v5.10.239","v5.10.238","v5.10.237","v5.10.236","v5.10.235","v5.10.234","v5.10.233","v5.10.232","v5.10.231","v5.10.230","v5.10.229","v5.10.228","v5.10.227","v5.10.226","v5.10.225","v5.10.224","v5.10.223","v5.10.222","v5.10.221","v5.10.220","v5.10.219","v5.10.218","v5.10.217","v5.10.216","v5.10.215","v5.10.214","v5.10.213","v5.10.212","v5.10.211","v5.10.210","v5.10.209","v5.10.208","v5.10.207","v5.10.206","v5.10.205","v5.10.204","v5.10.203","v5.10.202","v5.10.201","v5.10.200","v5.10.199","v5.10.198","v5.10.197","v5.10.196","v5.10.195","v5.10.194","v5.10.193","v5.10.192","v5.10.191","v5.10.190","v5.10.189","v5.10.188","v5.10.187","v5.10.186","v5.10.185","v5.10.184","v5.10.183","v5.10.182","v5.10.181","v5.10.180","v5.10.179","v5.10.178","v5.10.177","v5.10.176","v5.10.175","v5.10.174","v5.10.173","v5.10.172","v5.10.171","v5.10.170","v5.10.169","v5.10.168","v5.10.167","v5.10.166","v5.10.165","v5.10.164","v5.10.163","v5.10.162","v5.10.161","v5.10.160","v5.10.159","v5.10.158","v5.10.157","v5.10.156","v5.10.155","v5.10.154","v5.10.153","v5.10.152","v5.10.151","v5.10.150","v5.10.149","v5.10.148","v5.10.147","v5.10.146","v5.10.145","v5.10.144","v5.10.143","v5.10.142","v5.10.141","v5.10.140","v5.10.139","v5.10.138","v5.10.137","v5.10.136","v5.10.135","v5.10.134","v5.10.133","v5.10.132","v5.10.131","v5.10.130","v5.10.129","v5.10.128","v5.10.127","v5.10.126","v5.10.125","v5.10.124","v5.10.123","v5.10.122","v5.10.121","v5.10.120","v5.10.119","v5.10.118","v5.10.117","v5.10.116","v5.10.115","v5.10.114","v5.10.113","v5.10.112","v5.10.111","v5.10.110","v5.10.109","v5.10.108","v5.10.107","v5.10.106","v5.10.105","v5.10.104","v5.10.103","v5.10.102","v5.10.101","v5.10.100","v5.10.99","v5.10.98","v5.10.97","v5.10.96","v5.10.95","v5.10.94","v5.10.93","v5.10.92","v5.10.91","v5.10.90","v5.10.89","v5.10.88","v5.10.87","v5.10.86","v5.10.85","v5.10.84","v5.10.83","v5.10.82","v5.10.81","v5.10.80","v5.10.79","v5.10.78","v5.10.77","v5.10.76","v5.10.75","v5.10.74","v5.10.73","v5.10.72","v5.10.71","v5.10.70","v5.10.69","v5.10.68","v5.10.67","v5.10.66","v5.10.65","v5.10.64","v5.10.63","v5.10.62",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