diff --git a/libavformat/mov.c b/libavformat/mov.c
index 6490022b1d..e11c9f4457 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2886,6 +2886,7 @@ static int mov_read_stsz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     for (i = 0; i < entries && !pb->eof_reached; i++) {
         sc->sample_sizes[i] = get_bits_long(&gb, field_size);
         if (sc->sample_sizes[i] < 0) {
+            av_free(buf);
             av_log(c->fc, AV_LOG_ERROR, "Invalid sample size %d\n", sc->sample_sizes[i]);
             return AVERROR_INVALIDDATA;
         }