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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-74278

ALSA: seq: Fix kernel heap address leak in bounce_error_event()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix kernel heap address leak in bounce_error_event() The comment above bounce_error_event() documents that user clients should receive SNDRV_SEQ_EVENT_BOUNCE with the original event embedded as variable-length data, while kernel clients should receive SNDRV_SEQ_EVENT_KERNEL_ERROR with a quoted kernel pointer. However, the implementation unconditionally uses SNDRV_SEQ_EVENT_KERNEL_ERROR with data.quote.event set to the raw struct snd_seq_event pointer for all clients. When a bounce error event is delivered to a USER_CLIENT via snd_seq_read(), the kernel heap address in data.quote.event is exposed to userspace through copy_to_user() in the fixed-length branch. This is a distinct leak path from the one addressed by commit 705dd6dcbc0e ("ALSA: seq: Clear variable event pointer on read"), which sanitizes data.ext.ptr in the variable-length branch of snd_seq_read(). The bounce_error_event() leak uses fixed-length events that take the else branch where no sanitization occurs. Differentiate the bounce event by client type. For USER_CLIENT, send SNDRV_SEQ_EVENT_BOUNCE with SNDRV_SEQ_EVENT_LENGTH_VARIABLE and data.ext pointing to the original event. The variable-length path in snd_seq_event_dup() copies the event data into chained cells, and snd_seq_expand_var_event() copies only the content -- never the pointer -- to userspace. For KERNEL_CLIENT, keep the existing SNDRV_SEQ_EVENT_KERNEL_ERROR behavior with the quoted pointer.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 05e2358fec8812c37516ccea63bc4b9956d864baaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < eae296065ede41a24040e6a7c909ec970f78b4ebaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 93d260ce43a81df579c98bee92b91316df9c1c57affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < dae23c545eb5a2be3b27a82fd0f611894fb8ab69affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 0527a56cb327021cb73167cfddf0e49efa043500affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < efc86691e4d8083d9e380ea95042c2cf679f65fdaffected

Linux Linux

Default version status: affected

  • 2.6.12affected
  • 0 to < 2.6.12unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References