CVE-2026-68202
CVE CVE-2026-68202EUVD EUVD-2026-55303Published 2026-08-10T12:00:21.000Z
What the advisory describes
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.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6a10025c7fd09a7d2af37a3ae1da188569fce470; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <31a6163e301d832060f8236f1ed17cbc1ca198df; patch: 0; patch: 7.2-rc5; patch: 7.1.6; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb40d03ed792a8a8bf77aa0ee15df57b0ff78b07; patch: 6.6.148; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2c4dc0ed50b05cd847a4b34b8cebf0775f19aeb9; patch: 6.12.101; 2.6.12; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <24f0cabf173539f048946c8fc221131dc221f277; patch: 6.18.42
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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