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.
References
Configurations
Configuration 1 (hide)
|
History
12 Nov 2026, 16:24
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Linux linux Kernel
Linux |
|
| CWE | CWE-908 | |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| References | () https://git.kernel.org/stable/c/435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4 - Patch | |
| References | () https://git.kernel.org/stable/c/651ba82fe2a144bc7356d940bfd235c3810b0549 - Patch | |
| References | () https://git.kernel.org/stable/c/6ded42615fa1f4949925afd0a8a9e1ab3bf96202 - Patch | |
| References | () https://git.kernel.org/stable/c/a224c84e5d3d35708c082c84ad12d81d90762195 - Patch | |
| References | () https://git.kernel.org/stable/c/d7649aa11089a93ea2285c210397aa67e5800766 - Patch | |
| References | () https://git.kernel.org/stable/c/ea672a9f6cc38f06fe69dd2c257ef8a3d4db179a - Patch | |
| References | () https://git.kernel.org/stable/c/fb1aa5082847b98f44f9c6272aee9d0dca9244f0 - Patch | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 3.3 |
Information
Published : 2026-07-25 10:17
Updated : 2026-11-12 16:24
NVD link : CVE-2026-64479
Mitre link : CVE-2026-64479
CVE.ORG link : CVE-2026-64479
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-908
Use of Uninitialized Resource