{"id":"CVE-2026-74278","title":"ALSA: seq: Fix kernel heap address leak in bounce_error_event()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Fix kernel heap address leak in bounce_error_event()\n\nThe comment above bounce_error_event() documents that user clients\nshould receive SNDRV_SEQ_EVENT_BOUNC…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eae296065ede41a24040e6a7c909ec970f78b4eb","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 93d260ce43a81df579c98bee92b91316df9c1c57","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dae23c545eb5a2be3b27a82fd0f611894fb8ab69","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0527a56cb327021cb73167cfddf0e49efa043500","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < efc86691e4d8083d9e380ea95042c2cf679f65fd","Linux 2.6.12"],"published":"2026-08-15","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:45:16.258Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74278","references":[{"url":"https://git.kernel.org/stable/c/eae296065ede41a24040e6a7c909ec970f78b4eb"},{"url":"https://git.kernel.org/stable/c/93d260ce43a81df579c98bee92b91316df9c1c57"},{"url":"https://git.kernel.org/stable/c/dae23c545eb5a2be3b27a82fd0f611894fb8ab69"},{"url":"https://git.kernel.org/stable/c/0527a56cb327021cb73167cfddf0e49efa043500"},{"url":"https://git.kernel.org/stable/c/efc86691e4d8083d9e380ea95042c2cf679f65fd"}],"tags":["cve.org"],"epss":0.00168,"epssPercentile":0.05735,"ingestedAt":"2026-10-21T12:48:53.585Z","slug":"CVE-2026-74278","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Fix kernel heap address leak in bounce_error_event()\n\nThe comment above bounce_error_event() documents that user clients\nshould receive SNDRV_SEQ_EVENT_BOUNCE with the original event embedded\nas variable-length data, while kernel clients should receive\nSNDRV_SEQ_EVENT_KERNEL_ERROR with a quoted kernel pointer.\n\nHowever, the implementation unconditionally uses\nSNDRV_SEQ_EVENT_KERNEL_ERROR with data.quote.event set to the raw\nstruct snd_seq_event pointer for all clients.  When a bounce error\nevent is delivered to a USER_CLIENT via snd_seq_read(), the kernel\nheap address in data.quote.event is exposed to userspace through\ncopy_to_user() in the fixed-length branch.\n\nThis is a distinct leak path from the one addressed by commit\n705dd6dcbc0e (\"ALSA: seq: Clear variable event pointer on read\"),\nwhich sanitizes data.ext.ptr in the variable-length branch of\nsnd_seq_read().  The bounce_error_event() leak uses fixed-length\nevents that take the else branch where no sanitization occurs.\n\nDifferentiate the bounce event by client type.  For USER_CLIENT,\nsend SNDRV_SEQ_EVENT_BOUNCE with SNDRV_SEQ_EVENT_LENGTH_VARIABLE\nand data.ext pointing to the original event.  The variable-length\npath in snd_seq_event_dup() copies the event data into chained\ncells, and snd_seq_expand_var_event() copies only the content --\nnever the pointer -- to userspace.  For KERNEL_CLIENT, keep the\nexisting SNDRV_SEQ_EVENT_KERNEL_ERROR behavior with the quoted\npointer.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eae296065ede41a24040e6a7c909ec970f78b4eb`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 93d260ce43a81df579c98bee92b91316df9c1c57`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dae23c545eb5a2be3b27a82fd0f611894fb8ab69`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0527a56cb327021cb73167cfddf0e49efa043500`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < efc86691e4d8083d9e380ea95042c2cf679f65fd`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}