diff --git a/src/cron/c/expression.h b/src/cron/c/expression.h
index 4b40a96..3a5a530 100644
--- a/src/cron/c/expression.h
+++ b/src/cron/c/expression.h
@@ -11,7 +11,8 @@ typedef enum cron_parse_error {
 	cron_parse_invalid_expression = 1,
 	cron_parse_invalid_number = 2,
 	cron_parse_out_of_range = 3,
-	cron_parse_too_many_parts = 4
+	cron_parse_too_many_parts = 4,
+	cron_parse_not_enough_parts = 5
 } cron_parse_error;
 
 typedef struct cron_expression {
diff --git a/src/cron/c/parse.c b/src/cron/c/parse.c
index bb54191..10df78a 100644
--- a/src/cron/c/parse.c
+++ b/src/cron/c/parse.c
@@ -112,7 +112,7 @@ cron_parse_error ce_parse_part(uint64_t *out, char *s, uint8_t min,
 	*out = 0;
 
 	char *next;
-	enum cron_parse_error res;
+	cron_parse_error res;
 
 	while ((next = strchr(s, ',')) != NULL) {
 		next[0] = '\0';
@@ -180,13 +180,12 @@ uint8_t bf_to_nums(uint8_t **out, uint64_t bf, uint8_t min, uint8_t max) {
 /*
  * Parse a cron expression string into a cron_expression struct.
  */
-enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
+cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 	// The parsing functions modify the input string in-place
 	s = strdup(s);
 	char *orig_s = s;
 
-	enum cron_parse_error res = cron_parse_ok;
-	uint64_t bfs[max_parts];
+	cron_parse_error res = cron_parse_ok;
 
 	// First we divide the input string into its parts, divided by spaces.
 	// Each part is delimited by a NULL byte.
@@ -207,23 +206,19 @@ enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 		next[0] = '\0';
 		parts[part_count] = s;
 
+		part_count++;
+
 		// Skip multiple spaces
 		offset = 1;
 		while (next[offset] == ' ') {
 			offset++;
 		}
 		s = next + offset;
-
-		part_count++;
 	}
 
-	// The loop exited because we already have 4 parts, yet there's still at
-	// least one more part that follows.
-	if (next != NULL) {
-		res = cron_parse_too_many_parts;
-		goto end;
-	} else if (s[0] != '\0') {
-		// There's one more excessive trailing part
+	// Each iteration of the loop skips all trailing spaces. This means that, if
+	// s[0] isn't '\0', there's still another part before the end of the string.
+	if (s[0] != '\0') {
 		if (part_count == max_parts) {
 			res = cron_parse_too_many_parts;
 			goto end;
@@ -233,6 +228,11 @@ enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 		part_count++;
 	}
 
+	if (part_count < min_parts) {
+		res = cron_parse_not_enough_parts;
+		goto end;
+	}
+
 	// We now parse the parts in reverse. This is because the month part
 	// determines the maximum value of the day part.
 
@@ -268,6 +268,8 @@ enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 		res = ce_parse_part(&bit_field, parts[2], min[2], max_day_value);
 
 		if (res != cron_parse_ok) {
+			free(out->months);
+
 			goto end;
 		}
 
@@ -285,6 +287,9 @@ enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 	res = ce_parse_part(&bit_field, parts[1], min[1], max[1]);
 
 	if (res != cron_parse_ok) {
+		free(out->months);
+		free(out->days);
+
 		goto end;
 	}
 
@@ -296,6 +301,10 @@ enum cron_parse_error ce_parse_expression(cron_expression *out, char *s) {
 	res = ce_parse_part(&bit_field, parts[0], min[0], max[0]);
 
 	if (res != cron_parse_ok) {
+		free(out->months);
+		free(out->days);
+		free(out->hours);
+
 		goto end;
 	}
 
diff --git a/src/cron/expression.c.v b/src/cron/expression.c.v
index 0217ca3..217b687 100644
--- a/src/cron/expression.c.v
+++ b/src/cron/expression.c.v
@@ -73,6 +73,7 @@ enum ParseError as u8 {
 	invalid_number = 2
 	out_of_range = 3
 	too_many_parts = 4
+	not_enough_parts = 5
 }
 
 // str returns the string representation of a ParseError.
@@ -83,6 +84,7 @@ fn (e ParseError) str() string {
 		.invalid_number { 'Invalid number' }
 		.out_of_range { 'Out of range' }
 		.too_many_parts { 'Too many parts' }
+		.not_enough_parts { 'Not enough parts' }
 	}
 }
 
diff --git a/src/cron/parse_test.v b/src/cron/parse_test.v
index a44dffd..a143c73 100644
--- a/src/cron/parse_test.v
+++ b/src/cron/parse_test.v
@@ -24,6 +24,14 @@ fn test_not_allowed() {
 	res = false
 	parse_expression('0 /5') or { res = true }
 	assert res
+
+	res = false
+	parse_expression('0  ') or { res = true }
+	assert res
+
+	res = false
+	parse_expression('0') or { res = true }
+	assert res
 }
 
 fn test_leading_star() {
@@ -43,3 +51,7 @@ fn test_auto_extend() ! {
 
 	assert ce1 == ce2 && ce2 == ce3
 }
+
+fn test_four() {
+	parse_expression('0 1 2 3 ') or { assert false }
+}