{"id":"CVE-2026-72112","summary":"io_uring/bpf-ops: reject re-registration of an already-bound ops","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/bpf-ops: reject re-registration of an already-bound ops\n\nio_install_bpf() only rejects a second registration on the ctx side\n(ctx-\u003ebpf_ops) and sets the per-map back-pointer ops-\u003epriv\nunconditionally. The struct_ops link path never advances a map past\nBPF_STRUCT_OPS_STATE_READY, so the same io_uring_bpf_ops map can be\nregistered more than once, and bpf_io_reg() re-resolves the target ring\nvia fget(ops-\u003ering_fd) on every call. A caller can therefore point the\nsame ring_fd at a different io_ring_ctx between two BPF_LINK_CREATE\ncalls.\n\nThe second registration passes the ctx-\u003ebpf_ops check (the new ctx has\nnone) and overwrites ops-\u003epriv, orphaning the first ctx. Teardown\n(io_eject_bpf()/bpf_io_unreg()) only reaches a ctx through ops-\u003epriv, so\nthe orphaned ctx is never torn down: its ctx-\u003eloop_step keeps pointing\ninto the struct_ops trampoline, which is freed once the map is gone. A\nlater io_uring_enter() on the orphaned ring then calls the dangling\nctx-\u003eloop_step from io_run_loop() -- a use-after-free of freed\nexecutable memory, reachable by a task with CAP_BPF + CAP_PERFMON.\n\nReject registration when ops-\u003epriv is already set, as hid_bpf_reg()\ndoes for its struct_ops.","modified":"2026-08-18T03:56:20.282036995Z","published":"2026-08-15T05:52:53.275Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72112.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0639ea767fe04c288a8d6cb826100fe3d95d4936"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3afc64c61ce906a04f073ca350b46de10e8302f9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72112.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72112"},{"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":"98f37634b12b17ad5c56db8fb63cf9d7dc55d74c"},{"fixed":"0639ea767fe04c288a8d6cb826100fe3d95d4936"},{"fixed":"3afc64c61ce906a04f073ca350b46de10e8302f9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72112.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.1.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72112.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}