diff --git a/apply.c b/apply.c
index 1c0bcd737e..4b689d9bf7 100644
--- a/apply.c
+++ b/apply.c
@@ -1011,20 +1011,27 @@ static int gitdiff_newname(struct apply_state *state,
 				   DIFF_NEW_NAME);
 }
 
+static int parse_mode_line(const char *line, int linenr, unsigned int *mode)
+{
+	char *end;
+	*mode = strtoul(line, &end, 8);
+	if (end == line || !isspace(*end))
+		return error(_("invalid mode on line %d: %s"), linenr, line);
+	return 0;
+}
+
 static int gitdiff_oldmode(struct apply_state *state,
 			   const char *line,
 			   struct patch *patch)
 {
-	patch->old_mode = strtoul(line, NULL, 8);
-	return 0;
+	return parse_mode_line(line, state->linenr, &patch->old_mode);
 }
 
 static int gitdiff_newmode(struct apply_state *state,
 			   const char *line,
 			   struct patch *patch)
 {
-	patch->new_mode = strtoul(line, NULL, 8);
-	return 0;
+	return parse_mode_line(line, state->linenr, &patch->new_mode);
 }
 
 static int gitdiff_delete(struct apply_state *state,
@@ -1138,7 +1145,7 @@ static int gitdiff_index(struct apply_state *state,
 	memcpy(patch->new_sha1_prefix, line, len);
 	patch->new_sha1_prefix[len] = 0;
 	if (*ptr == ' ')
-		patch->old_mode = strtoul(ptr+1, NULL, 8);
+		return gitdiff_oldmode(state, ptr + 1, patch);
 	return 0;
 }
 
diff --git a/t/t4129-apply-samemode.sh b/t/t4129-apply-samemode.sh
index c268298eaf..5cdd76dfa7 100755
--- a/t/t4129-apply-samemode.sh
+++ b/t/t4129-apply-samemode.sh
@@ -13,7 +13,9 @@ test_expect_success setup '
 	echo modified >file &&
 	git diff --stat -p >patch-0.txt &&
 	chmod +x file &&
-	git diff --stat -p >patch-1.txt
+	git diff --stat -p >patch-1.txt &&
+	sed "s/^\(new mode \).*/\1/" <patch-1.txt >patch-empty-mode.txt &&
+	sed "s/^\(new mode \).*/\1garbage/" <patch-1.txt >patch-bogus-mode.txt
 '
 
 test_expect_success FILEMODE 'same mode (no index)' '
@@ -59,4 +61,16 @@ test_expect_success FILEMODE 'mode update (index only)' '
 	git ls-files -s file | grep "^100755"
 '
 
+test_expect_success FILEMODE 'empty mode is rejected' '
+	git reset --hard &&
+	test_must_fail git apply patch-empty-mode.txt 2>err &&
+	test_i18ngrep "invalid mode" err
+'
+
+test_expect_success FILEMODE 'bogus mode is rejected' '
+	git reset --hard &&
+	test_must_fail git apply patch-bogus-mode.txt 2>err &&
+	test_i18ngrep "invalid mode" err
+'
+
 test_done