CVE-2026-50142 libheif: unbounded heap allocation in HEIF sequence parser (stsz fixed-size mode missing bound check)

libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.0, a crafted HEIF sequence accepted by heifcontextreadfrommemory with the msf1 sequence brand can cause unbounded heap allocation. In libheif/sequences/seqboxes.cc, Boxstsz::parse applies maxsequenceframes only to...