There exists a NULL pointer dereference in ff_vc1_parse_frame_header_adv in vc1.c in Libav 12.3, which allows attackers to cause a denial-of-service through a crafted aac file.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:H6.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H