GHSA-87F3-MHHQ-WFVX
Vulnerability from github – Published: 2026-05-01 15:30 – Updated: 2026-05-01 15:30In 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.
{
"affected": [],
"aliases": [
"CVE-2026-31778"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-01T15:16:41Z",
"severity": null
},
"details": "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": "GHSA-87f3-mhhq-wfvx",
"modified": "2026-05-01T15:30:35Z",
"published": "2026-05-01T15:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31778"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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- 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.