{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-80970",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-08-26T14:34:25.810Z",
        "datePublished": "2026-09-11T19:42:33.789Z",
        "dateUpdated": "2026-10-19T08:45:54.980Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-10-19T08:45:54.980Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: FCP: do not copy out an uninitialised init response\n\nfcp_ioctl_init() allocates its response buffer with kmalloc() and copies\nthe whole buffer back to userspace:\n\n\tbuf_size = init.step0_resp_size + init.step2_resp_size;\n\n\tvoid *resp __free(kfree) =\n\t\tkmalloc(buf_size, GFP_KERNEL);\n\t...\n\tif (copy_to_user(arg->resp, resp, buf_size))\n\t\treturn -EFAULT;\n\nNothing clears the buffer, and the only writer of its leading\nstep0_resp_size bytes is the step-0 control transfer:\n\n\terr = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),\n\t\tFCP_USB_REQ_STEP0,\n\t\tUSB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,\n\t\t0, private->bInterfaceNumber,\n\t\tstep0_resp, private->step0_resp_size);\n\tif (err < 0)\n\t\treturn err;\n\nusb_fill_control_urb() does not set URB_SHORT_NOT_OK, so a short or\nzero-length data stage completes with status 0 and snd_usb_ctl_msg()\nreturns a small actual_length.  The only check is err < 0, so a short\ntransfer is accepted as success.\n\nsnd_usb_ctl_msg() copies the full size back unconditionally:\n\n\tbuf = kmemdup(data, size, GFP_KERNEL);\n\t...\n\tmemcpy(data, buf, size);\n\nBytes the device never wrote are therefore restored into resp unchanged\nand copied to userspace.  step0_resp_size and step2_resp_size are each\nvalidated only to 1..255, so the caller also picks the slab cache, from\nkmalloc-8 up to kmalloc-512.\n\nOn 7.2.0-rc5 (arm64), device answering step 0 with a zero-length data\nstage, s0 = s2 = 255:\n\n  # init_on_alloc off, no spray\n  step0 window [0,255): nonzero=94/255\n  000: 00 80 60 06 00 00 ff ff 18 00 00 00 57 01 ea 01\n  010: 08 78 22 13 00 00 ff ff a8 c4 5f 80 00 80 ff ff\n\n  # same kernel, kmalloc-512 pre-seeded with an 8-byte tag\n  step0 window [0,255): nonzero=219/255  tagbytes=232\n\n  # identical run, init_on_alloc=1\n  step0 window [0,255): nonzero=0/255  tagbytes=0\n\n  # all three runs\n  step2 window [255,510): device words matched=62/62\n\na8 c4 5f 80 00 80 ff ff is the little-endian kernel text address\nffff8000805fc4a8.  The step-2 window is unaffected, so the disclosure is\nexactly the step-0 region.\n\nZero the buffer, and require the step-0 transfer to deliver the full\nstep0_resp_size bytes so a short data stage is reported as an error.\n\nDiscovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>"
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "sound/usb/fcp.c"
                    ],
                    "versions": [
                        {
                            "version": "46757a3e7d50dac923888e7fbe68377736f13c70",
                            "lessThan": "e9e52437120fb5f802152877ba20c4b406c9fa9e",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "46757a3e7d50dac923888e7fbe68377736f13c70",
                            "lessThan": "29ab2df278ab4f1d238cd9c1c393ee00db175cba",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "46757a3e7d50dac923888e7fbe68377736f13c70",
                            "lessThan": "4335e387786479889e6db691fe06d345e52ea536",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "sound/usb/fcp.c"
                    ],
                    "versions": [
                        {
                            "version": "6.14",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.14",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.52",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.4",
                            "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": "6.14",
                                    "versionEndExcluding": "6.18.52"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.14",
                                    "versionEndExcluding": "7.2.4"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.14",
                                    "versionEndExcluding": "7.3"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/e9e52437120fb5f802152877ba20c4b406c9fa9e"
                },
                {
                    "url": "https://git.kernel.org/stable/c/29ab2df278ab4f1d238cd9c1c393ee00db175cba"
                },
                {
                    "url": "https://git.kernel.org/stable/c/4335e387786479889e6db691fe06d345e52ea536"
                }
            ],
            "title": "ALSA: FCP: do not copy out an uninitialised init response",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}