{"id":"CVE-2026-80628","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: oss: Serialize readq reset state with q->lock\n\nsnd_seq_oss_readq_clear() resets qlen, head, and tail without\nq->lock even though the normal reader and produc…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: oss: Serialize readq reset state with q->lock\n\nsnd_seq_oss_readq_clear() resets qlen, head, and tail without\nq->lock even though the normal reader and produc…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-08-28","updated":"2026-08-29","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-80628","references":[{"url":"https://git.kernel.org/stable/c/287d506d4e0865918cec82bb1361f283a08c979b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/43e10709b1ba288bcbabb9b9cb6e518b2a5d8506","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/49ce92d207820f588b0406add82f053decfbe5d9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00127,"epssPercentile":0.02715,"ingestedAt":"2026-08-29T23:43:56.405Z","slug":"CVE-2026-80628","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: oss: Serialize readq reset state with q->lock\n\nsnd_seq_oss_readq_clear() resets qlen, head, and tail without\nq->lock even though the normal reader and producer paths serialize the\nsame ring state under that spinlock. A reset can therefore race\nsnd_seq_oss_readq_free() or snd_seq_oss_readq_put_event() and leave\nstale records in the queue, drop freshly queued ones, or report the\nwrong readiness after wakeup. KCSAN reports a data race between\nsnd_seq_oss_readq_clear() and snd_seq_oss_readq_free().\n\nTake q->lock while clearing the ring and resetting input_time. Factor\nthe enqueue logic into a caller-locked helper so\nsnd_seq_oss_readq_put_timestamp() updates its suppression state under\nthe same lock instead of racing the reset path.\n\nThe buggy scenario involves two paths, with each column showing the\norder within that path:\n\nreset path:                      locked readq updater:\n1. snd_seq_oss_reset() or        1. A reader or callback producer\n   release reaches                  takes q->lock on the same queue.\n   snd_seq_oss_readq_clear().\n2. snd_seq_oss_readq_clear()     2. The updater tests or modifies\n   resets qlen, head, tail,         qlen, head, and tail.\n   and input_time.\n3. snd_seq_oss_readq_clear()     3. The updater completes its\n   wakes sleepers on                read-modify-write sequence.\n   q->midi_sleep.\n4. Without q->lock, the reset    4. The resulting ring state drives\n   can overlap the locked           later reads and readiness.\n   update.\n\nKCSAN reports:\n\nBUG: KCSAN: data-race in snd_seq_oss_readq_clear /\nsnd_seq_oss_readq_free\n\nwrite to 0xffff8881069fe608 of 4 bytes by task 120516 on cpu 0:\n  snd_seq_oss_readq_free+0x6c/0x80\n  snd_seq_oss_read+0xcb/0x250\n  odev_read+0x38/0x60\n  vfs_read+0xff/0x600\n  ksys_read+0xb4/0x140\n  __x64_sys_read+0x46/0x60\n  do_syscall_64+0xbb/0x2f0\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nread to 0xffff8881069fe608 of 4 bytes by task 120517 on cpu 1:\n  snd_seq_oss_readq_clear+0x1f/0x90\n  snd_seq_oss_reset+0xa7/0xf0\n  snd_seq_oss_ioctl+0x6f6/0x7e0\n  odev_ioctl+0x56/0xc0\n  __x64_sys_ioctl+0xd1/0x120\n  do_syscall_64+0xbb/0x2f0\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nvalue changed: 0x00000001 -> 0x00000000\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}