CVE-2026-64479

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An uninitialized heap leak exists in the ALSA sequencer. The snd seq event dup() function copies an incoming event into a pool cell. In UMP-enabled builds, a check is performed to clear the cell->ump.raw.extra word if the copied size is less than sizeof(cell->event). However, for legacy non-UMP events, the size equals sizeof(cell->event), causing the condition to be false and leaving stale data in the extra word. Because the cell pool is allocated with kvmalloc() and reused via a free list, this word may contain uninitialized heap or leftover event data. An unprivileged client using /dev/snd/seq with SNDRV SEQ FILTER NO CONVERT enabled can trigger snd seq read() to read this as a larger snd seq ump event structure, resulting in a 4-byte kernel heap information leak to user space.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.