{"id":"CVE-2026-81009","summary":"io_uring/query: cap user size passed to copy_struct_to_user","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/query: cap user size passed to copy_struct_to_user\n\nio_handle_query_entry() clamps hdr.size for the inbound copy_from_user()\nbut keeps the original user value as usize. copy_struct_to_user() uses\nthat usize and, when it is larger than the kernel result, clear_user()s\nthe trailing bytes.\n\nAs hdr.size is a __u32, a query can request nearly 4 GiB of zeroing,\nincluding on the error path where res_size stays 0. The interface is\nreachable without a ring via IORING_REGISTER_QUERY.\n\nReject sizes larger than PAGE_SIZE, as recommended for copy_struct_*\ninterfaces.","modified":"2026-09-13T03:47:10.163378879Z","published":"2026-09-11T19:43:00.074Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81009.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2b8ad4981ecedb14c1fdd811ab977010b23933e6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/417e02f7b6051765b91cf1289071882eebd172e0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81009.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81009"},{"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":"c265ae75f900cea4e415230a77b5d152377627dd"},{"fixed":"417e02f7b6051765b91cf1289071882eebd172e0"},{"fixed":"2b8ad4981ecedb14c1fdd811ab977010b23933e6"},{"fixed":"ba77efee1b95b4ad7559b1cdbe7cd7fa36dca95b"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81009.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.18.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81009.json"}}],"schema_version":"1.9.0"}