CVE-2026-31778 (GCVE-0-2026-31778)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-01 14:15
VLAI?
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 02d9c5b0b5553a391448b6d655262bd829f90234 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 66194c2575a4f567577ae70b1d7561163ce791a6 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < a82c1bce2d1299dd3c686a8fe48cf75b79a403c7 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 3178b62e2e31bab39f63d4c8e54bf4ee0a425627 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 3afa2e67f3523a980a2f90fd63c22322ac2b9ce0 (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 7594a6464873d90fd229e5b94cdd3b92c9feabed (git)
Affected: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a , < 45424e871abf2a152e247a9cff78359f18dd95c0 (git)
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    Linux Linux Affected: 2.6.31
Unaffected: 0 , < 2.6.31 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.134 , ≤ 6.6.* (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "sound/usb/caiaq/device.c"
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        {
          "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."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-05-01T14:15:05.804Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"
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      "title": "ALSA: caiaq: fix stack out-of-bounds read in init_card",
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    "dateReserved": "2026-03-09T15:48:24.140Z",
    "dateUpdated": "2026-05-01T14:15:05.804Z",
    "state": "PUBLISHED"
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  }
}


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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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