diff --git a/.github/workflows/tabula.vscode.yaml b/.github/workflows/tabula.vscode.yaml
index 974c7cc..d451617 100644
--- a/.github/workflows/tabula.vscode.yaml
+++ b/.github/workflows/tabula.vscode.yaml
@@ -10,7 +10,7 @@ on:
   workflow_dispatch:
 
 env:
-  NODE_VERSION: 20.x
+  NODE_VERSION: 24.x
 
 jobs:
   tabula_vscode:
diff --git a/internal/markdown/process.go b/internal/markdown/process.go
index 71d5f0e..be65b2f 100644
--- a/internal/markdown/process.go
+++ b/internal/markdown/process.go
@@ -1,9 +1,11 @@
 package markdown
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"strings"
+	"sync"
 
 	"github.com/pblazh/tabula/internal/csv"
 )
@@ -18,60 +20,88 @@ func Process(
 		return err
 	}
 
-	var result []chunk
+	result := make([][]*chunk, len(chunks))
+	var wg sync.WaitGroup
+	var mu sync.Mutex
+	var errs []error
 
-	for i := range chunks {
-		ch := chunks[i]
-		write := csv.Write
-		wrap := wrapCodeBlock
+	for i, ch := range chunks {
+		result[i] = make([]*chunk, 0)
+		scriptChunk := getScriptChunk(chunks, i)
 
-		if ch.kind == csvKind && config.Align {
-			write = csv.WriteAligned
+		if chunkNeedsProcessing(&ch, scriptChunk) {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				output, err := processChunk(config, &ch, scriptChunk)
+				if err != nil {
+					mu.Lock()
+					errs = append(errs, err)
+					mu.Unlock()
+					return
+				}
+				result[i] = output
+			}()
+			continue
 		}
+		result[i] = append(result[i], &ch)
+	}
 
-		if ch.kind == tableKind {
-			write = WriteAligned
-			wrap = wrapTable
-		}
+	wg.Wait()
 
-		scriptChunk := getScriptChunk(chunks, i)
-		if chunkNeedsProcessing(&ch, scriptChunk) {
-			data, comments, err := execute(config, &ch, scriptChunk)
-			if err != nil {
-				result = append(result, ch)
-				result = append(
-					result,
-					chunk{
-						kind: messageKind,
-						text: []string{toMessage(err.Error())},
-					},
-				)
-				continue
-			}
+	if err := errors.Join(errs...); err != nil {
+		return err
+	}
 
-			// create a formatter depending on if align was requested
-			var sb strings.Builder
-			err = write(&sb, data, comments)
+	for _, chs := range result {
+		for _, ch := range chs {
+			_, err = fmt.Fprintf(writer, "%s\n", ch)
 			if err != nil {
-				return ErrWriteCSV(err)
+				return ErrWriteMD(err)
 			}
+		}
+	}
 
-			lines := wrap(sb.String())
+	return nil
+}
 
-			result = append(result, chunk{kind: csvKind, text: lines})
-			continue
-		}
-		result = append(result, ch)
+func processChunk(config *Config, data, script *chunk) ([]*chunk, error) {
+	var result []*chunk
+	lines, comments, err := execute(config, data, script)
+	if err != nil {
+		result = append(result, data)
+		result = append(
+			result,
+			&chunk{
+				kind: messageKind,
+				text: []string{toMessage(err.Error())},
+			},
+		)
+		return result, nil
 	}
 
-	for _, ch := range result {
-		_, err = fmt.Fprintf(writer, "%s\n", ch)
-		if err != nil {
-			return ErrWriteMD(err)
-		}
+	write := csv.Write
+	wrap := wrapCodeBlock
+
+	if data.kind == csvKind && config.Align {
+		write = csv.WriteAligned
 	}
 
-	return nil
+	if data.kind == tableKind {
+		write = WriteAligned
+		wrap = wrapTable
+	}
+	// create a formatter depending on if align was requested
+	var sb strings.Builder
+	err = write(&sb, lines, comments)
+	if err != nil {
+		return nil, ErrWriteCSV(err)
+	}
+
+	output := wrap(sb.String())
+
+	result = append(result, &chunk{kind: csvKind, text: output})
+	return result, nil
 }
 
 func wrapCodeBlock(code string) []string {
diff --git a/internal/markdown/processor_test.go b/internal/markdown/processor_test.go
index 2ec3411..20d7cab 100644
--- a/internal/markdown/processor_test.go
+++ b/internal/markdown/processor_test.go
@@ -2,6 +2,7 @@ package markdown
 
 import (
 	"strings"
+	"sync"
 	"testing"
 )
 
@@ -335,6 +336,45 @@ func TestProcess(t *testing.T) {
 				"",
 			}, "\n"),
 		},
+		{
+			name: "multiple CSV with code concurrent",
+			input: strings.Join([]string{
+				"```csv",
+				"one,two,three",
+				"1,2,3",
+				"```",
+				"```tabula",
+				"let A2 = 10;",
+				"```",
+				"",
+				"```csv",
+				"one,two,three",
+				"4,5,6",
+				"```",
+				"```tabula",
+				"let A2 = 20;",
+				"```",
+				"",
+			}, "\n"),
+			output: strings.Join([]string{
+				"```csv",
+				"one,two,three",
+				"10,2,3",
+				"```",
+				"```tabula",
+				"let A2 = 10;",
+				"```",
+				"",
+				"```csv",
+				"one,two,three",
+				"20,5,6",
+				"```",
+				"```tabula",
+				"let A2 = 20;",
+				"```",
+				"",
+			}, "\n"),
+		},
 	}
 
 	for _, tc := range cases {
@@ -357,3 +397,65 @@ func TestProcess(t *testing.T) {
 		})
 	}
 }
+
+// TestProcessConcurrentChunks verifies that multiple processable chunks in a
+// single document are each executed with their own correct script and data.
+// This guards against closure variable capture bugs where goroutines share
+// loop variables and all end up processing the last chunk's data.
+func TestProcessConcurrentChunks(t *testing.T) {
+	input := strings.Join([]string{
+		"```csv",
+		"one,two,three",
+		"1,2,3",
+		"```",
+		"```tabula",
+		"let A2 = 10;",
+		"```",
+		"",
+		"```csv",
+		"one,two,three",
+		"4,5,6",
+		"```",
+		"```tabula",
+		"let A2 = 20;",
+		"```",
+		"",
+	}, "\n")
+
+	want := strings.Join([]string{
+		"```csv",
+		"one,two,three",
+		"10,2,3",
+		"```",
+		"```tabula",
+		"let A2 = 10;",
+		"```",
+		"",
+		"```csv",
+		"one,two,three",
+		"20,5,6",
+		"```",
+		"```tabula",
+		"let A2 = 20;",
+		"```",
+		"",
+	}, "\n")
+
+	const iterations = 100
+	var wg sync.WaitGroup
+	wg.Add(iterations)
+	for range iterations {
+		go func() {
+			defer wg.Done()
+			var writer strings.Builder
+			if err := Process(&Config{}, strings.NewReader(input), &writer); err != nil {
+				t.Errorf("unexpected error: %s", err)
+				return
+			}
+			if got := writer.String(); got != want {
+				t.Errorf("concurrent output mismatch:\nwant: %q\n got: %q", want, got)
+			}
+		}()
+	}
+	wg.Wait()
+}