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ALSA: caiaq: fix stack out-of-bounds read in init_card

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.253, 5.15.203, 6.1.168, 6.12.81, 6.18.22, 6.19.12, 6.6.134
CVEs
CVE-2026-31778
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 05:19 UTC · Revision 1

Source evidence

ALSA: caiaq: fix stack out-of-bounds read in init_card

core-osv · Original source

Published 1 May 2026, 14:15 UTC

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.

osv:CVE-2026-31778

Kernel

Fixed versions: 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12

Complete source record
{
  "id": "355ca8ceceaf44d8f908403a0e695506aba3e38cff817b5e5ca5108302a78fa3",
  "url": "https://osv.dev/vulnerability/CVE-2026-31778",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALSA: caiaq: fix stack out-of-bounds read in init_card",
    "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.",
    "evidence": "osv:CVE-2026-31778",
    "products": [
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          "value": "Kernel",
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        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.253",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.203",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.168",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.134",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.81",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.22",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.12",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-31778",
      "aliases": [
        "CVE-2026-31778"
      ],
      "affected": [
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        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.31"
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                {
                  "fixed": "5.10.253"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "5.11.0"
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                  "introduced": "5.16.0"
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                  "introduced": "6.7.0"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                },
                {
                  "fixed": "6.18.22"
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            },
            {
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            "ecosystem": "Linux"
          },
          "database_specific": {
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          }
        }
      ],
      "modified": "2026-10-28T02:30:26.292148886Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234",
        "https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627",
        "https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0",
        "https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6",
        "https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0",
        "https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6",
        "https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed",
        "https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31778.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31778",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31778.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31778",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492680,
  "published_at": "2026-05-01T14:15:05.804+00:00"
}