{"id":"CVE-2026-64523","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: Take a long-lived file reference at submit\n\nhandshake_nl_accept_doit() needs the file pointer backing\nreq->hr_sk->sk_socket to survive the window between…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: Take a long-lived file reference at submit\n\nhandshake_nl_accept_doit() needs the file pointer backing\nreq->hr_sk->sk_socket to survive the window between…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-25","updated":"2026-08-09","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64523","references":[{"url":"https://git.kernel.org/stable/c/09dba37eee70d0596e26645015f1aa95a9848e9d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/16eaba5aa89c04eea125905bb8f988c1897f4f29","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/685b10dd0e32c7782cead16c8cf055c609678583","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b913801ad9b9a51437d84d030ec6843e08976bd6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00359,"epssPercentile":0.29719,"ingestedAt":"2026-08-09T19:34:41.265Z","slug":"CVE-2026-64523","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: Take a long-lived file reference at submit\n\nhandshake_nl_accept_doit() needs the file pointer backing\nreq->hr_sk->sk_socket to survive the window between\nhandshake_req_next() and the subsequent FD_PREPARE() and get_file().\nThe submit-side sock_hold() does not provide that.  sk_refcnt keeps\nstruct sock alive, but struct socket is owned by sock->file: when\nthe consumer fputs the last file reference, sock_release() tears\nthe socket down regardless of any sock_hold.\n\nAdd an hr_file pointer to struct handshake_req and acquire an\nexplicit reference on sock->file during handshake_req_submit().\nhandshake_complete() and handshake_req_cancel() release the\nreference on the completion-bit-winning path.\n\nThe submit error path must also release the file reference, but\nafter rhashtable insertion a concurrent handshake_req_cancel() can\ndiscover the request and race the error path.  Gate the error-path\ncleanup -- sk_destruct restoration, fput, and request destruction\n-- with test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED), the same\nserialization handshake_complete() and handshake_req_cancel()\nalready use.  When cancel has already claimed ownership, the submit\nerror path returns without touching the request; socket teardown\nhandles final destruction.\n\nThe accept-side dereferences are not yet retargeted; that change\ncomes in the next patch.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}