CVE-2026-74503

CVE CVE-2026-74503EUVD EUVD-2026-59696Veröffentlicht 2026-08-15T12:27:28.000ZZuletzt geändert 2026-08-17T05:47:54.000ZCVSS 7.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Clear SNDRV_TIMER_IFLG_DEAD once the close completes snd_timer_close_locked() marks an instance with SNDRV_TIMER_IFLG_DEAD and returns early when the flag is already set, but the flag is never cleared again. A completed close ends in remove_slave_links(), which leaves timeri->timer NULL, so a second close is already harmless through the timer == NULL path; the early return can only be reached by an instance that was opened again in between. For such an instance the close unlinks nothing, so snd_timer_instance_free() frees an object that is still on timer->open_list_head, still on snd_timer_master_list if it was opened with a slave key, still owns any adopted slaves, and still holds its timer and module references. snd_seq_timer_open() reopens an instance exactly like that: it retries its fallback open on the same object after a failure that has already run snd_timer_close_locked() internally. An unprivileged user with access to /dev/snd/timer and /dev/snd/seq can force that failure, since snd_timer_check_master() returns -EBUSY when a pending slave matches the new master's (slave_class, slave_id) key and the target timer has reached max_instances, and SNDRV_TIMER_IOCTL_SELECT with dev_class = SNDRV_TIMER_CLASS_SLAVE keeps the caller-supplied dev_sclass, so a sequencer queue's key can be forged. The freed instance is afterwards dereferenced by any further snd_timer_open() on that timer, by snd_timer_check_slave(), and by /proc/asound/timers, which faults on the stale ti->owner pointer. The flag only has to be visible while the close is in progress, which is all its other users need. Clear it in remove_slave_links(), under the same timer->lock that sets it, once the instance is off every list.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux 7.0.13 <7.1; patch: 7.1.8; 60e73ab87b84bbd6bd7ddd1d16019a3a3705ab8f; 586b219a22b1032b28b8bd356b963276c5e5bf53 <bb016091010ec401a06e6bdace0cd944ee03d371; 6.12.94 <6.12.103; 6.18.36 <6.18.44; patch: 0; patch: 6.18.44; patch: 6.12.103; patch: 7.2; da3039e91d1f835874ed6e9a33ea19ee80c2cb92 <0c561fab50991df10b1e4daca25886c34a2a9c07; f46093dd22969037beb1fce2e043f3236be41c92 <a26a2e52736f9e39843ca66a2e1ce6bf1adbcd1e; 7.1; da3039e91d1f835874ed6e9a33ea19ee80c2cb92 <c2744d5f3aea474513fd2298daecb94a952ce441

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.