CVE-2026-31778 (GCVE-0-2026-31778)
Vulnerability from cvelistv5
Published
2026-05-01 14:15
Modified
2026-05-01 14:15
Severity ?
VLAI Severity ?
EPSS score ?
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
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a Version: bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a |
||
{
"containers": {
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"status": "unaffected",
"version": "0",
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},
{
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"status": "unaffected",
"version": "5.10.253",
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},
{
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"status": "unaffected",
"version": "5.15.203",
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},
{
"lessThanOrEqual": "6.1.*",
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"version": "6.1.168",
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},
{
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},
{
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"version": "6.12.81",
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},
{
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"status": "unaffected",
"version": "6.18.22",
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"status": "unaffected",
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{
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}
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}
],
"cpeApplicability": [
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],
"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."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-01T14:15:05.804Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234"
},
{
"url": "https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"
},
{
"url": "https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6"
},
{
"url": "https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"
},
{
"url": "https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627"
},
{
"url": "https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"
},
{
"url": "https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed"
},
{
"url": "https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"
}
],
"title": "ALSA: caiaq: fix stack out-of-bounds read in init_card",
"x_generator": {
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}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31778",
"datePublished": "2026-05-01T14:15:05.804Z",
"dateReserved": "2026-03-09T15:48:24.140Z",
"dateUpdated": "2026-05-01T14:15:05.804Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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