CVE-2026-53241

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ALSA: seq: dummy: fix UMP event stack overread<br /> <br /> The dummy sequencer port forwards events by copying an incoming<br /> struct snd_seq_event into a stack temporary, rewriting source and<br /> destination, and dispatching the temporary to subscribers. That legacy<br /> event storage is smaller than struct snd_seq_ump_event.<br /> <br /> When a UMP event reaches the dummy client, the copy leaves the UMP flag<br /> set but only provides legacy-sized stack storage. The subscriber<br /> delivery path then uses snd_seq_event_packet_size() and copies a<br /> UMP-sized packet from that stack object, reading past the end of the<br /> temporary.<br /> <br /> Use the existing union __snd_seq_event storage and copy the packet size<br /> reported for the incoming event before rewriting the common routing<br /> fields. This preserves the full UMP packet for UMP events while keeping<br /> legacy event handling unchanged.