From 90f1f797aa9231375e4858df523fbfeda89bfd79 Mon Sep 17 00:00:00 2001 From: Frank Plowman Date: Wed, 24 Dec 2025 15:35:06 +0000 Subject: [PATCH] lavc/vvc: Error on inter slice with no reference pics The semantics of sh_num_ref_idx_active_minus1[ i ] state that When the current slice is a P slice, the value of NumRefIdxActive[ 0 ] shall be greater than 0. When the current slice is a B slice, both NumRefIdxActive[ 0 ] and NumRefIdxActive[ 1 ] shall be greater than 0. Fixes: use of uninitialized memory Fixes: 449549597/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VVC_fuzzer-5600497089445888 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reported-by: Michael Niedermayer michael@niedermayer.cc --- libavcodec/cbs_h266_syntax_template.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libavcodec/cbs_h266_syntax_template.c b/libavcodec/cbs_h266_syntax_template.c index 8b337c75d0..d9a65a9c19 100644 --- a/libavcodec/cbs_h266_syntax_template.c +++ b/libavcodec/cbs_h266_syntax_template.c @@ -3248,6 +3248,12 @@ static int FUNC(slice_header) (CodedBitstreamContext *ctx, RWContext *rw, FFMIN(ref_pic_lists->rpl_ref_list[i].num_ref_entries, pps->pps_num_ref_idx_default_active_minus1[i] + 1); } + + if (current->num_ref_idx_active[i] <= 0) { + av_log(ctx->log_ctx, AV_LOG_ERROR, + "Inter slice but no reference pictures available for RPL%d.\n", i); + return AVERROR_INVALIDDATA; + } } else { current->num_ref_idx_active[i] = 0; }