FKIE_CVE-2026-31778

Vulnerability from fkie_nvd - Published: 2026-05-01 15:16 - Updated: 2026-05-01 15:24
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: caiaq: fix stack out-of-bounds read in init_card The loop creates a whitespace-stripped copy of the card shortname where `len < sizeof(card->id)` is used for the bounds check. Since sizeof(card->id) is 16 and the local id buffer is also 16 bytes, writing 16 non-space characters fills the entire buffer, overwriting the terminating nullbyte. When this non-null-terminated string is later passed to snd_card_set_id() -> copy_valid_id_string(), the function scans forward with `while (*nid && ...)` and reads past the end of the stack buffer, reading the contents of the stack. A USB device with a product name containing many non-ASCII, non-space characters (e.g. multibyte UTF-8) will reliably trigger this as follows: BUG: KASAN: stack-out-of-bounds in copy_valid_id_string sound/core/init.c:696 [inline] BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c sound/core/init.c:718 The off-by-one has been present since commit bafeee5b1f8d ("ALSA: snd_usb_caiaq: give better shortname") from June 2009 (v2.6.31-rc1), which first introduced this whitespace-stripping loop. The original code never accounted for the null terminator when bounding the copy. Fix this by changing the loop bound to `sizeof(card->id) - 1`, ensuring at least one byte remains as the null terminator.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: caiaq: fix stack out-of-bounds read in init_card\n\nThe loop creates a whitespace-stripped copy of the card shortname\nwhere `len \u003c sizeof(card-\u003eid)` is used for the bounds check. Since\nsizeof(card-\u003eid) is 16 and the local id buffer is also 16 bytes,\nwriting 16 non-space characters fills the entire buffer,\noverwriting the terminating nullbyte.\n\nWhen this non-null-terminated string is later passed to\nsnd_card_set_id() -\u003e copy_valid_id_string(), the function scans\nforward with `while (*nid \u0026\u0026 ...)` and reads past the end of the\nstack buffer, reading the contents of the stack.\n\nA USB device with a product name containing many non-ASCII, non-space\ncharacters (e.g. multibyte UTF-8) will reliably trigger this as follows:\n\n  BUG: KASAN: stack-out-of-bounds in copy_valid_id_string\n       sound/core/init.c:696 [inline]\n  BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c\n       sound/core/init.c:718\n\nThe off-by-one has been present since commit bafeee5b1f8d (\"ALSA:\nsnd_usb_caiaq: give better shortname\") from June 2009 (v2.6.31-rc1),\nwhich first introduced this whitespace-stripping loop. The original\ncode never accounted for the null terminator when bounding the copy.\n\nFix this by changing the loop bound to `sizeof(card-\u003eid) - 1`,\nensuring at least one byte remains as the null terminator."
    }
  ],
  "id": "CVE-2026-31778",
  "lastModified": "2026-05-01T15:24:14.893",
  "metrics": {},
  "published": "2026-05-01T15:16:41.190",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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