CVE-2026-120246: FFmpeg 4.4 through 9.0.2 Uninitialized Memory Disclosure via CDXL HAM Decoder

FFmpeg 4.4 through 9.0.2 contains a use of uninitialized variable vulnerability in the CDXL decoder that leaks stack memory into decoded pixels via unfilled HAM palette entries. Attackers can craft a type-0 CDXL file whose HAM pixels select unfilled newpalette entries in cdxldecodeham8() or cdxldecodeham6(), exposing stack bytes and pointer fragments in the BGR24 output.