{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90001", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.780Z", "datePublished": "2026-09-16T10:33:12.063Z", "dateUpdated": "2026-10-19T08:56:15.260Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:56:15.260Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: bpf: serialize device reference release in struct_ops destroy path\n\n__hid_bpf_ops_destroy_device() and hid_bpf_unreg() can race on the\nsame registration reference, double-putting struct hid_device and\nfreeing it while hid_destroy_device() still uses it. Serialize the\nremove/NULL decision under hdev->bpf.prog_list_lock so exactly one\npath releases each registration reference: unreg re-checks ops->hdev\nunder the lock and returns without putting when the destroy path\nalready cleared it; all put_device() calls happen after the lock is\ndropped, which is safe because a concurrent unreg then observes\nops->hdev == NULL under the lock.\n\nBackground: each successful attach (hid_bpf_ops_reg) acquires one\ndevice reference (hid_get_device()). Two paths can release it:\n\n- device destruction: hid_destroy_device() -> hid_bpf_destroy_device()\n -> __hid_bpf_ops_destroy_device(), which walks hdev->bpf.prog_list\n under rcu_read_lock() and drops one reference per attached program;\n- BPF link release: bpf map delete (no BPF_F_LINK) synchronously calls\n st_ops->unreg() -> hid_bpf_unreg(), which drops the reference for\n its own registration.\n\nThe coordination handshake (e->hdev = NULL on the destroy side vs\n\"if (!hdev) return\" on the unreg side) is a TOCTOU check: the two\npaths run under different lock domains (rcu_read_lock vs\nprog_list_lock), so a concurrent unreg can read ops->hdev as\nnon-NULL, block on prog_list_lock, and then proceed while the\ndestroy traversal executes - both paths then drop the same\nreference. The refcount reaches zero legitimately (each decrement\nis individually valid), so no refcount_t saturation fires: the\ndevice is simply freed while the transport is still inside\nhid_destroy_device(), and subsequent teardown touches freed memory.\n\nThe fix serializes the remove/NULL decision under prog_list_lock on\nboth sides and moves the destroy-side puts outside the lock. With\nthe lock held, plain reads/writes of ops->hdev are sufficient; no\nREAD_ONCE/WRITE_ONCE are added, keeping the patch minimal.\n\nUnlocked-read safety: the unlocked read of ops->hdev at the top of\nhid_bpf_unreg() cannot touch a freed device, because the unreg path\nitself still holds this registration's reference (released only by\nits own hid_put_device() after the lock is dropped), and a destroy\ntraversal that already cleared ops->hdev makes the lock-internal\nre-check return early without any put. At most one of the two\npaths releases each registration reference." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - HID-BPF attach and unreg are reached only through local bpf() syscalls (BPF_MAP_TYPE_STRUCT_OPS / BPF_PROG_TYPE_STRUCT_OPS). Concurrent hid_destroy_device() is also local (uhid UHID_DESTROY/close or HID teardown), not a network or adjacent-radio packet path.\nAC:L - The attacker controls both sides of the TOCTOU race: attach HID-BPF, then concurrently delete the struct_ops map (hid_bpf_unreg) and destroy the HID device (e.g. uhid close). Destroy never took prog_list_lock, so unreg does not block on it and the double-put is reliably hittable.\nPR:L - Loading STRUCT_OPS maps/programs requires CAP_BPF and CAP_PERFMON, which can be delegated via BPF tokens into user namespaces rather than init-namespace root. /dev/uhid is also granted to the seat user on typical desktop systems, so real root is not required.\nUI:N - The attacker creates their own uhid HID device, loads and attaches HID-BPF struct_ops, then races map delete against device destroy in their own processes. No victim action such as plugging in hardware or mounting a filesystem is required.\nS:U - The double-put use-after-free of struct hid_device stays inside the host kernel HID/BPF authority and is a standard local privilege-escalation primitive, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - Double-putting struct hid_device frees it while hid_destroy_device() still uses it. Use-after-free of this large kobject, which holds driver callbacks and pointers, enables an attacker-controlled kernel memory read primitive.\nI:H - The same use-after-free lets the attacker reclaim the freed hid_device via heap spray and corrupt ll_driver/hiddev function pointers or adjacent heap objects, yielding arbitrary kernel writes and control-flow hijacking.\nA:H - Even without full exploitation, dropping the hid_device refcount to zero while hid_remove_device()/put_device() still run causes a kernel oops, panic, or hang on the subsequent use of freed memory." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/hid/bpf/hid_bpf_struct_ops.c" ], "versions": [ { "version": "ebc0d8093e8c97de459615438edefad1a4ac352c", "lessThan": "401359684620145be710de97b87e1a47abfe1459", "status": "affected", "versionType": "git" }, { "version": "ebc0d8093e8c97de459615438edefad1a4ac352c", "lessThan": "c7f927aa8b55008ed5ea0814313d5dad771dcf3c", "status": "affected", "versionType": "git" }, { "version": "ebc0d8093e8c97de459615438edefad1a4ac352c", "lessThan": "bfb7939788f3c8dd080a4dd81e38d625b35d194e", "status": "affected", "versionType": "git" }, { "version": "ebc0d8093e8c97de459615438edefad1a4ac352c", "lessThan": "9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/hid/bpf/hid_bpf_struct_ops.c" ], "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/401359684620145be710de97b87e1a47abfe1459" }, { "url": "https://git.kernel.org/stable/c/c7f927aa8b55008ed5ea0814313d5dad771dcf3c" }, { "url": "https://git.kernel.org/stable/c/bfb7939788f3c8dd080a4dd81e38d625b35d194e" }, { "url": "https://git.kernel.org/stable/c/9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0" } ], "title": "HID: bpf: serialize device reference release in struct_ops destroy path", "x_generator": { "engine": "bippy-1.2.0" } } } }