CVE-2026-62377 libheif: Reachable assertion in HeifContext::get_track() aborts on a valid-but-empty HEIF sequence file (context.cc:2110)

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heifcontextreadfrommemory can leave the context with no registered sequence tracks and crash when heifcontextgettrackctx, 0 is called. HeifContext::gettrack in libheif/context.cc...