CVE-2026-30754A memory corruption vulnerability exists in FFmpeg before 8.1. The RTP encoding process. In the nal_send function in libavformat/rtpenc_h264_hevc.c, a negative size parameter (size=-3) is passed to memcpy when transmitting H.264/HEVC streams via RTP using a crafted input file. This was detected using AddressSanitizer.