{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40094", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.163Z", "datePublished": "2025-10-30T09:48:02.446Z", "dateUpdated": "2026-08-05T12:07:45.475Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:45.475Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_acm: Refactor bind path to use __free()\n\nAfter an bind/unbind cycle, the acm->notify_req is left stale. If a\nsubsequent bind fails, the unified error label attempts to free this\nstale request, leading to a NULL pointer dereference when accessing\nep->ops->free_request.\n\nRefactor the error handling in the bind path to use the __free()\nautomatic cleanup mechanism.\n\nUnable to handle kernel NULL pointer dereference at virtual address 0000000000000020\nCall trace:\n usb_ep_free_request+0x2c/0xec\n gs_free_req+0x30/0x44\n acm_bind+0x1b8/0x1f4\n usb_add_function+0xcc/0x1f0\n configfs_composite_bind+0x468/0x588\n gadget_bind_driver+0x104/0x270\n really_probe+0x190/0x374\n __driver_probe_device+0xa0/0x12c\n driver_probe_device+0x3c/0x218\n __device_attach_driver+0x14c/0x188\n bus_for_each_drv+0x10c/0x168\n __device_attach+0xfc/0x198\n device_initial_probe+0x14/0x24\n bus_probe_device+0x94/0x11c\n device_add+0x268/0x48c\n usb_add_gadget+0x198/0x28c\n dwc3_gadget_init+0x700/0x858\n __dwc3_set_mode+0x3cc/0x664\n process_scheduled_works+0x1d8/0x488\n worker_thread+0x244/0x334\n kthread+0x114/0x1bc\n ret_from_fork+0x10/0x20" } ], "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 - The bind/unbind/re-bind sequence that creates and then dereferences the stale `acm->notify_req` is driven entirely by local writes to `/sys/kernel/config/usb_gadget//UDC` (or legacy gadget module load); no USB traffic from an attached host is needed, so the bug is reachable through local filesystem/syscall access rather than requiring physical port access.\nAC:L - The attacker deterministically controls every step — the successful first bind, the unbind that leaves `acm->notify_req` dangling, and the forced failure of the next bind by exhausting `usb_interface_id()`/`usb_ep_autoconfig()` through functions added to the config between cycles — plus the heap spray that reclaims the freed `usb_request`. No race or uncontrolled condition is involved.\nPR:L - Only write access to the USB gadget configfs tree is required; `acm_bind()` performs no capability check, and on Android and embedded/industrial deployments USB function switching is routinely delegated to non-root system/daemon accounts that own that tree.\nUI:N - The attacker performs all configfs writes itself; no cable plug event, victim action, or interaction with another user is required to reach the stale free.\nS:U - The dangling-pointer free corrupts kernel heap state within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `gs_free_req()` reads `req->buf` out of the reclaimed `struct dwc3_request` slab and `ep->ops` out of a freed `struct dwc3_ep`, so an attacker who grooms those caches gains object-overlap and arbitrary-free primitives that are readily converted into kernel memory disclosure.\nI:H - `kfree()` of an attacker-controlled pointer read from the freed request, a double free through `dwc3_gadget_ep_free_request()`, and an indirect call through a reclaimable `ep->ops` table together yield classic heap-corruption primitives leading to arbitrary write and privilege escalation.\nA:H - The observed effect is a kernel oops — NULL/garbage `ep->ops` dereference in `usb_ep_free_request()` — and the double free independently causes slab corruption and panic, which the attacker can trigger repeatedly." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/f_acm.c" ], "versions": [ { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "c5d116862dd3ed162d079738a5ebddf9fceea850", "status": "affected", "versionType": "git" }, { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175", "status": "affected", "versionType": "git" }, { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "e348d18fb0124b662cfefb3001733b49da428215", "status": "affected", "versionType": "git" }, { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "201a66d8e6630762e760e1d78f1d149da1691e7b", "status": "affected", "versionType": "git" }, { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "c4301e4dd6b32faccb744f1c2320e64235b68d3b", "status": "affected", "versionType": "git" }, { "version": "1f1ba11b64947051fc32aa15fcccef6463b433f7", "lessThan": "47b2116e54b4a854600341487e8b55249e926324", "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/usb/gadget/function/f_acm.c" ], "versions": [ { "version": "2.6.27", "status": "affected" }, { "version": "0", "lessThan": "2.6.27", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.196", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.158", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.114", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.55", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.5", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "2.6.27", "versionEndExcluding": "5.15.196" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.1.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.6.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.12.55" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.17.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.27", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c5d116862dd3ed162d079738a5ebddf9fceea850" }, { "url": "https://git.kernel.org/stable/c/2b1546f7c5fc6c44555a8e7a2b34229d1dcd2175" }, { "url": "https://git.kernel.org/stable/c/e348d18fb0124b662cfefb3001733b49da428215" }, { "url": "https://git.kernel.org/stable/c/201a66d8e6630762e760e1d78f1d149da1691e7b" }, { "url": "https://git.kernel.org/stable/c/c4301e4dd6b32faccb744f1c2320e64235b68d3b" }, { "url": "https://git.kernel.org/stable/c/47b2116e54b4a854600341487e8b55249e926324" } ], "title": "usb: gadget: f_acm: Refactor bind path to use __free()", "x_generator": { "engine": "bippy-1.2.0" } } } }