In the Linux kernel, the following vulnerability has been resolved:
ASoC: dapm: Fix off-by-one check on the second enum channel
The snd_soc_dapm_put_enum_double() rejects item[0] once it reaches
e->items, but it lets item[1] be equal to it. Both go on to
snd_soc_enum_item_to_val(), which indexes e->values with no bound of
its own, so an enum with a value table reads one element past the end.
The indexing arrived with the MUX consolidation, which relaxed the
item[1] check in the same hunk. The value MUX handler it deleted used
= there, and the snd_soc_put_enum_double() in soc-ops.c still does.
Only adav80x pairs a value table with two shifts, and its second
channel looks accidental, but the control does report two values.
Writing three into it reads off the end of adav80x_mux_values. The
core catches that only under CONFIG_SND_CTL_INPUT_VALIDATION, which
defaults off.