{"id":"CVE-2025-38196","summary":"io_uring/rsrc: validate buffer count with offset for cloning","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: validate buffer count with offset for cloning\n\nsyzbot reports that it can trigger a WARN_ON() for kmalloc() attempt\nthat's too big:\n\nWARNING: CPU: 0 PID: 6488 at mm/slub.c:5024 __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024\nModules linked in:\nCPU: 0 UID: 0 PID: 6488 Comm: syz-executor312 Not tainted 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 PREEMPT\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\npstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024\nlr : __do_kmalloc_node mm/slub.c:-1 [inline]\nlr : __kvmalloc_node_noprof+0x3b4/0x640 mm/slub.c:5012\nsp : ffff80009cfd7a90\nx29: ffff80009cfd7ac0 x28: ffff0000dd52a120 x27: 0000000000412dc0\nx26: 0000000000000178 x25: ffff7000139faf70 x24: 0000000000000000\nx23: ffff800082f4cea8 x22: 00000000ffffffff x21: 000000010cd004a8\nx20: ffff0000d75816c0 x19: ffff0000dd52a000 x18: 00000000ffffffff\nx17: ffff800092f39000 x16: ffff80008adbe9e4 x15: 0000000000000005\nx14: 1ffff000139faf1c x13: 0000000000000000 x12: 0000000000000000\nx11: ffff7000139faf21 x10: 0000000000000003 x9 : ffff80008f27b938\nx8 : 0000000000000002 x7 : 0000000000000000 x6 : 0000000000000000\nx5 : 00000000ffffffff x4 : 0000000000400dc0 x3 : 0000000200000000\nx2 : 000000010cd004a8 x1 : ffff80008b3ebc40 x0 : 0000000000000001\nCall trace:\n __kvmalloc_node_noprof+0x520/0x640 mm/slub.c:5024 (P)\n kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]\n io_rsrc_data_alloc io_uring/rsrc.c:206 [inline]\n io_clone_buffers io_uring/rsrc.c:1178 [inline]\n io_register_clone_buffers+0x484/0xa14 io_uring/rsrc.c:1287\n __io_uring_register io_uring/register.c:815 [inline]\n __do_sys_io_uring_register io_uring/register.c:926 [inline]\n __se_sys_io_uring_register io_uring/register.c:903 [inline]\n __arm64_sys_io_uring_register+0x42c/0xea8 io_uring/register.c:903\n __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\n invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49\n el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132\n do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151\n el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767\n el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786\n el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600\n\nwhich is due to offset + buffer_count being too large. The registration\ncode checks only the total count of buffers, but given that the indexing\nis an array, it should also check offset + count. That can't exceed\nIORING_MAX_REG_BUFFERS either, as there's no way to reach buffers beyond\nthat limit.\n\nThere's no issue with registrering a table this large, outside of the\nfact that it's pointless to register buffers that cannot be reached, and\nthat it can trigger this kmalloc() warning for attempting an allocation\nthat is too large.","modified":"2026-04-02T12:47:52.605367Z","published":"2025-07-04T13:37:19.191Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38196.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0e23ac818f3afb16660b0ba384875d56a7013879"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1d27f11bf02b38c431e49a17dee5c10a2b4c2e28"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38196.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38196"},{"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":"b16e920a1909da6799c43000db730d8fcdcae907"},{"fixed":"0e23ac818f3afb16660b0ba384875d56a7013879"},{"fixed":"1d27f11bf02b38c431e49a17dee5c10a2b4c2e28"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38196.json"}}],"schema_version":"1.7.5"}