diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 626261ab24..8c6be84017 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -203,6 +203,9 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
             return offset1;
         offset += offset1;
     }
+    if (offset < 0)
+        return AVERROR(EINVAL);
+
     offset1 = offset - pos;
     if (!s->must_flush &&
         offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {