{
  "cveId": "CVE-2026-80970",
  "url": "https://patchblox.com/security/cve/CVE-2026-80970",
  "summary": "CVE-2026-80970 is fixed in linux on 1 platform by DEBIAN-CVE-2026-80970 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ALSA: FCP: do not copy out an uninitialised init...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ALSA: FCP: do not copy out an uninitialised init response  fcp_ioctl_init() allocates its response buffer with kmalloc() and copies the whole buffer back to userspace:  \tbuf_size = init.step0_resp_size \u002B init.step2_resp_size;  \tvoid *resp __free(kfree) = \t\tkmalloc(buf_size, GFP_KERNEL); \t... \tif (copy_to_user(arg-\u003Eresp, resp, buf_size)) \t\treturn -EFAULT;  Nothing clears the buffer, and the only writer of its leading step0_resp_size bytes is the step-0 control transfer:  \terr = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), \t\tFCP_USB_REQ_STEP0, \t\tUSB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN, \t\t0, private-\u003EbInterfaceNumber, \t\tstep0_resp, private-\u003Estep0_resp_size); \tif (err \u003C 0) \t\treturn err;  usb_fill_control_urb() does not set URB_SHORT_NOT_OK, so a short or zero-length data stage completes with status 0 and snd_usb_ctl_msg() returns a small actual_length.  The only check is err \u003C 0, so a short transfer is accepted as success.  snd_usb_ctl_msg() copies the full size back unconditionally:  \tbuf = kmemdup(data, size, GFP_KERNEL); \t... \tmemcpy(data, buf, size);  Bytes the device never wrote are therefore restored into resp unchanged and copied to userspace.  step0_resp_size and step2_resp_size are each validated only to 1..255, so the caller also picks the slab cache, from kmalloc-8 up to kmalloc-512.  On 7.2.0-rc5 (arm64), device answering step 0 with a zero-length data stage, s0 = s2 = 255:    # init_on_alloc off, no spray   step0 window [0,255): nonzero=94/255   000: 00 80 60 06 00 00 ff ff 18 00 00 00 57 01 ea 01   010: 08 78 22 13 00 00 ff ff a8 c4 5f 80 00 80 ff ff    # same kernel, kmalloc-512 pre-seeded with an 8-byte tag   step0 window [0,255): nonzero=219/255  tagbytes=232    # identical run, init_on_alloc=1   step0 window [0,255): nonzero=0/255  tagbytes=0    # all three runs   step2 window [255,510): device words matched=62/62  a8 c4 5f 80 00 80 ff ff is the little-endian kernel text address ffff8000805fc4a8.  The step-2 window is unaffected, so the disclosure is exactly the step-0 region.  Zero the buffer, and require the step-0 transfer to deliver the full step0_resp_size bytes so a short data stage is reported as an error.  Discovered by XBOW, triaged by Baul Lee \u003Cbaul.lee@xbow.com\u003E",
  "published": "2026-09-11T20:19:03Z",
  "severity": "",
  "epss": 0.00206,
  "epssPercentile": 0.10769,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-80970",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-80970",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}