CVE-2026-74339 (GCVE-0-2026-74339)
Vulnerability from cvelistv5
Published
2026-08-15 05:58
Modified
2026-08-17 05:17
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Clear variable event pointer on read
snd_seq_read() copies a queued variable-length event header to userspace
before expanding the payload. Queued variable-length events use
SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first
extension cell.
The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the
copy, but it leaves data.ext.ptr untouched. A userspace sequencer client
can therefore write a direct variable event to itself and read back the
extension-cell kernel address from the returned header.
Clear the temporary header pointer before copy_to_user(). The original
queued event remains unchanged and is still passed to
snd_seq_expand_var_event(), so payload expansion keeps using the
internal chain.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 |
||
{
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"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
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},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
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{
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"status": "unaffected",
"version": "6.18.40",
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{
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"status": "unaffected",
"version": "7.1.5",
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"descriptions": [
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Clear variable event pointer on read\n\nsnd_seq_read() copies a queued variable-length event header to userspace\nbefore expanding the payload. Queued variable-length events use\nSNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first\nextension cell.\n\nThe read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the\ncopy, but it leaves data.ext.ptr untouched. A userspace sequencer client\ncan therefore write a direct variable event to itself and read back the\nextension-cell kernel address from the returned header.\n\nClear the temporary header pointer before copy_to_user(). The original\nqueued event remains unchanged and is still passed to\nsnd_seq_expand_var_event(), so payload expansion keeps using the\ninternal chain."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:17:31.258Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207"
},
{
"url": "https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8"
},
{
"url": "https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a"
},
{
"url": "https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5"
},
{
"url": "https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b"
},
{
"url": "https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee"
},
{
"url": "https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76"
}
],
"title": "ALSA: seq: Clear variable event pointer on read",
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-74339",
"datePublished": "2026-08-15T05:58:29.888Z",
"dateReserved": "2026-08-15T05:44:03.885Z",
"dateUpdated": "2026-08-17T05:17:31.258Z",
"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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