{"api_version":"1","generated_at":"2026-09-14T03:10:43+00:00","cve":"CVE-2026-80970","urls":{"html":"https://cve.report/CVE-2026-80970","api":"https://cve.report/api/cve/CVE-2026-80970.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80970","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80970"},"summary":{"title":"ALSA: FCP: do not copy out an uninitialised init response","description":"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>","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:03","updated_at":"2026-09-11 20:19:03"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/4335e387786479889e6db691fe06d345e52ea536","name":"https://git.kernel.org/stable/c/4335e387786479889e6db691fe06d345e52ea536","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/29ab2df278ab4f1d238cd9c1c393ee00db175cba","name":"https://git.kernel.org/stable/c/29ab2df278ab4f1d238cd9c1c393ee00db175cba","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80970","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80970","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 46757a3e7d50dac923888e7fbe68377736f13c70 29ab2df278ab4f1d238cd9c1c393ee00db175cba git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 46757a3e7d50dac923888e7fbe68377736f13c70 4335e387786479889e6db691fe06d345e52ea536 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80970","cve":"CVE-2026-80970","epss":"0.001890000","percentile":"0.086800000","score_date":"2026-09-13","updated_at":"2026-09-14 00:18:03"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["sound/usb/fcp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"29ab2df278ab4f1d238cd9c1c393ee00db175cba","status":"affected","version":"46757a3e7d50dac923888e7fbe68377736f13c70","versionType":"git"},{"lessThan":"4335e387786479889e6db691fe06d345e52ea536","status":"affected","version":"46757a3e7d50dac923888e7fbe68377736f13c70","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["sound/usb/fcp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.14"},{"lessThan":"6.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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>"}],"providerMetadata":{"dateUpdated":"2026-09-11T19:42:33.789Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80970","datePublished":"2026-09-11T19:42:33.789Z","dateReserved":"2026-08-26T14:34:25.810Z","dateUpdated":"2026-09-11T19:42:33.789Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:03","lastModifiedDate":"2026-09-11 20:19:03","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80970","Ordinal":"1","Title":"ALSA: FCP: do not copy out an uninitialised init response","CVE":"CVE-2026-80970","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80970","Ordinal":"1","NoteData":"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>","Type":"Description","Title":"ALSA: FCP: do not copy out an uninitialised init response"}]}}}