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vuln-cve/data/2026/80xxx/CVE-2026-80970.json
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{
"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"
}
}
}
}