CVE-2026-68202ALSA: seq: close a re-opened queue timer in the destructor
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: close a re-opened queue timer in the destructor queue_delete() closes the queue timer, then frees it. snd_seq_timer_close() clears q->timer->timeri. snd_use_lock_sync() then drains borrowers, and snd_seq_timer_delete() frees q->timer. A borrower can re-open the timer inside that window. A SET_QUEUE_CLIENT that took a queueptr() use_lock reference before the queue was unlinked runs snd_seq_timer_open() after the close. Open refuses re-open only while timeri is set, and the close just cleared it, so it re-opens timeri. snd_seq_timer_delete() does not close that instance. Its snd_seq_timer_stop() is a no-op, because running was cleared first. So it frees q->timer with the instance still live. The queue is freed next. The instance stays on the global timer with callback_data pointing at the freed queue. A non-owner START on the unlocked queue arms it. The next tick derefs the freed queue in snd_seq_timer_interrupt(). Reachable by an unprivileged user with access to /dev/snd/seq. No CAP and no queue ownership required. Close any lingering instance in the destructor. There, ->timeri can no longer change: the queue is unlinked and all use_lock borrowers have drained, so no snd_seq_queue_use() can re-open it. Close it before clearing q->timer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt() to finish, and that callback still reads q->timer (via snd_seq_check_queue()), so q->timer must stay valid until it drains.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b7feeaca1f53b10df9b4de9eaf611767ca70dc92; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 7478ef94b49bc9789cf1a003deec58b42283dde4; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 9d9be6fc30f384f92c4e1b8ed40bd9d4796b7833; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 24f0cabf173539f048946c8fc221131dc221f277; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 6a10025c7fd09a7d2af37a3ae1da188569fce470; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 31a6163e301d832060f8236f1ed17cbc1ca198df; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9 | CNA record |
References
- https://git.kernel.org/stable/c/b7feeaca1f53b10df9b4de9eaf611767ca70dc92
- https://git.kernel.org/stable/c/7478ef94b49bc9789cf1a003deec58b42283dde4
- https://git.kernel.org/stable/c/9d9be6fc30f384f92c4e1b8ed40bd9d4796b7833
- https://git.kernel.org/stable/c/fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07
- https://git.kernel.org/stable/c/24f0cabf173539f048946c8fc221131dc221f277
- https://git.kernel.org/stable/c/6a10025c7fd09a7d2af37a3ae1da188569fce470
- https://git.kernel.org/stable/c/31a6163e301d832060f8236f1ed17cbc1ca198df
- https://git.kernel.org/stable/c/2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.