diff --git a/Tests/images/p_8.tga b/Tests/images/p_8.tga
new file mode 100644
index 000000000..73759a282
Binary files /dev/null and b/Tests/images/p_8.tga differ
diff --git a/Tests/test_file_tga.py b/Tests/test_file_tga.py
index 87a59ff3d..75c592da2 100644
--- a/Tests/test_file_tga.py
+++ b/Tests/test_file_tga.py
@@ -7,7 +7,7 @@ from pathlib import Path
 
 import pytest
 
-from PIL import Image
+from PIL import Image, UnidentifiedImageError
 
 from .helper import assert_image_equal, assert_image_equal_tofile, hopper
 
@@ -65,6 +65,11 @@ def test_sanity(mode, tmp_path: Path) -> None:
                     roundtrip(original_im)
 
 
+def test_palette_depth_8(tmp_path: Path) -> None:
+    with pytest.raises(UnidentifiedImageError):
+        Image.open("Tests/images/p_8.tga")
+
+
 def test_palette_depth_16(tmp_path: Path) -> None:
     with Image.open("Tests/images/p_16.tga") as im:
         assert_image_equal_tofile(im.convert("RGB"), "Tests/images/p_16.png")
diff --git a/src/PIL/TgaImagePlugin.py b/src/PIL/TgaImagePlugin.py
index 5d4827525..b6748c25e 100644
--- a/src/PIL/TgaImagePlugin.py
+++ b/src/PIL/TgaImagePlugin.py
@@ -128,6 +128,9 @@ class TgaImageFile(ImageFile.ImageFile):
                 self.palette = ImagePalette.raw(
                     "BGRA", b"\0" * 4 * start + self.fp.read(4 * size)
                 )
+            else:
+                msg = "unknown TGA map depth"
+                raise SyntaxError(msg)
 
         # setup tile descriptor
         try: