libavcodec/pthread_frame.c in FFmpeg before 5.1.2, as used in VLC and other products, leaves stale hwaccel state in worker threads, which allows attackers to trigger a use-after-free and execute arbitrary code in some circumstances (e.g., hardware re-initialization upon a mid-video SPS change when Direct3D11 is used).
A null pointer dereference issue was discovered in 'FFmpeg' in decode_main_header() function of libavformat/nutdec.c file. The flaw occurs because the function lacks check of the return value of avformat_new_stream() and triggers the null pointer dereference error, causing an application to crash.
An issue was discovered in the FFmpeg package, where vp3_decode_frame in libavcodec/vp3.c lacks check of the return value of av_malloc() and will cause a null pointer dereference, impacting availability.
Prior to ffmpeg version 4.3, the tty demuxer did not have a 'read_probe' function assigned to it. By crafting a legitimate "ffconcat" file that references an image, followed by a file the triggers the tty demuxer, the contents of the second file will be copied into the output file verbatim (as long as the `-vcodec copy` option is passed to ffmpeg).
In FFmpeg before 4.2, avcodec_open2 in libavcodec/utils.c allows a NULL pointer dereference and possibly unspecified other impact when there is no valid close function pointer.
FFmpeg through 4.2 has a "Conditional jump or move depends on uninitialised value" issue in h2645_parse because alloc_rbsp_buffer in libavcodec/h2645_parse.c mishandles rbsp_buffer.
aa_read_header in libavformat/aadec.c in FFmpeg before 3.2.14 and 4.x before 4.1.4 does not check for sscanf failure and consequently allows use of uninitialized variables.