ALSA: seq: Fix uninitialised heap leak in snd_seq_event_dup()
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix uninitialised heap leak in snd_seq_event_dup() snd_seq_event_dup() copies an incoming event into a pool cell and, in the UMP-enabled build, clears the trailing cell->ump.raw.extra word that the memcpy() did not cover. The guard deciding whether to clear it compares the copied size against sizeof(cell->event): memcpy(&cell->ump, event, size); if (size < sizeof(cell->event)) cell->ump.raw.extra = 0; For a legacy (non-UMP) event, size == sizeof(struct snd_seq_event) == sizeof(cell->event), so the condition is false and the extra word keeps stale data. The cell pool is allocated with kvmalloc() (not zeroed) and cells are reused via a free list, so that word holds uninitialised heap or leftover event data. When such a cell is delivered to a UMP client (client->midi_version > 0) that set SNDRV_SEQ_FILTER_NO_CONVERT -- so the legacy event reaches it unconverted -- snd_seq_read() reads it out as the larger struct snd_seq_ump_event and copies the stale word to user space, a 4-byte kernel heap infoleak to an unprivileged /dev/snd/seq client. Compare against sizeof(cell->ump) instead, so the trailing word is zeroed for every event shorter than the UMP cell.
CVE-2026-64479
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:CVE-2026-64479
Kernel
Source reference: /affected/1/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 6.6.145
Source reference:
/affected/1/ranges6.12.96Source reference:
/affected/1/ranges6.18.39Source reference:
/affected/1/ranges7.1.4Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "6389f2c135311c4ce7c08c3b29145c8f95aacf1f"
},
{
"fixed": "d7649aa11089a93ea2285c210397aa67e5800766"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "d7e2ce72833bb23a82b4201fbed7214cc04a4a8c"
},
{
"fixed": "a224c84e5d3d35708c082c84ad12d81d90762195"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "46397622a3fa8372b8fda0f04b33d16923b03b1b"
},
{
"fixed": "ea672a9f6cc38f06fe69dd2c257ef8a3d4db179a"
},
{
"fixed": "fb1aa5082847b98f44f9c6272aee9d0dca9244f0"
},
{
"fixed": "651ba82fe2a144bc7356d940bfd235c3810b0549"
},
{
"fixed": "6ded42615fa1f4949925afd0a8a9e1ab3bf96202"
},
{
"fixed": "435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4"
}
]
}
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64479.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.5.0"
},
{
"fixed": "6.6.145"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.7.0"
},
{
"fixed": "6.12.96"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.13.0"
},
{
"fixed": "6.18.39"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.19.0"
},
{
"fixed": "7.1.4"
}
]
}
],
"package": {
"name": "Kernel",
"ecosystem": "Linux"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64479.json"
}
}
]- Related CVEs
- CVE-2026-64479
Source reference:
/id
Publisher severity
No explicit severity was provided.
- Event
- #50665 · Revision 1
- Added to Heist Feed
- Publisher date