{"id":"CVE-2026-64424","summary":"netpoll: fix a use-after-free on shutdown path","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetpoll: fix a use-after-free on shutdown path\n\nThere is a use-after-free error on netpoll, which is clearly detected by\nKASAN.\n\n      BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3b/0x80\n      Read of size 1 at addr ... by task kworker/9:1\n      Workqueue: events queue_process\n      Call Trace:\n       skb_dequeue+0x1e/0xb0\n       queue_process+0x2c/0x600\n       process_scheduled_works+0x4b6/0x850\n       worker_thread+0x414/0x5a0\n      Allocated by task 242:\n       __netpoll_setup+0x201/0x4a0\n       netpoll_setup+0x249/0x550\n       enabled_store+0x32f/0x380\n      Freed by task 0:\n       kfree+0x1b7/0x540\n       rcu_core+0x3f8/0x7a0\n\nThe problem happens when there is a pending TX worker running in\nparallel with the cleanup path.\n\nThis is what happens on netpoll shutdown path:\n\n1) __netpoll_cleanup() is called\n2) set dev-\u003enpinfo to NULL\n3) call_rcu() with rcu_cleanup_netpoll_info()\n  3.1) rcu_cleanup_netpoll_info() tries to cancel all workers with\n       cancel_delayed_work(), but doesn't wait for the worker to finish\n4) and kfree(npinfo);\n\nBecause 3.1) doesn't really cancel the work, as the comment says \"we\ncan't call cancel_delayed_work_sync here, as we are in softirq\", the TX\nworker can run after 4).\n\nTl;DR: queue_process() is not an RCU reader, it reaches npinfo through\nthe work item via container_of().\n\nUse disable_delayed_work_sync() to ensure the worker is completely\nstopped and prevent any future re-arming attempts. Once npinfo is set\nto NULL, senders will bail out and not queue new work. The disable flag\nensures any in-flight re-arming attempts also fail silently.\n\nIn the future, we can do the cleanup inline here without needing the\nnpinfo-\u003ercu rcu_head, but that is net-next material.","modified":"2026-07-27T04:03:22.079809117Z","published":"2026-07-25T08:51:02.276Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64424.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/45f1458a85017a023f138b22ac5c76abd477db42"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5ed09a108d93a3b002cc79823d9455b50c4a8be7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/95ecc5b58042f6b6743b589e6588f1cd7ba336aa"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a33f37f8d079da7236ed7b7e2aed2a34ab81e7cf"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64424.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64424"},{"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":"38e6bc185d9544dfad1774b3f8902a0b061aea25"},{"fixed":"95ecc5b58042f6b6743b589e6588f1cd7ba336aa"},{"fixed":"a33f37f8d079da7236ed7b7e2aed2a34ab81e7cf"},{"fixed":"5ed09a108d93a3b002cc79823d9455b50c4a8be7"},{"fixed":"45f1458a85017a023f138b22ac5c76abd477db42"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64424.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.6.0"},{"fixed":"6.12.96"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64424.json"}}],"schema_version":"1.7.5"}