diff --git a/src/cron/expression/c/expression.c b/src/cron/expression/c/expression.c
index c990b4f..f9dc534 100644
--- a/src/cron/expression/c/expression.c
+++ b/src/cron/expression/c/expression.c
@@ -48,7 +48,7 @@ int ce_next(struct cron_simple_time *out, struct cron_expression *ce, struct cro
 				// Minute is the only value where we explicitely make sure we
 				// can't match sref's value exactly. This is to ensure we only
 				// return values in the future.
-                while (minute_index < ce->minute_count && ref->minute > ce->minutes[minute_index]) {
+                while (minute_index < ce->minute_count && ref->minute >= ce->minutes[minute_index]) {
                     minute_index++;
                 }
             }
@@ -91,7 +91,7 @@ int ce_next(struct cron_simple_time *out, struct cron_expression *ce, struct cro
         }
     }
 
-    out->month = ce->months[month_index * ce->month_count];
+    out->month = ce->months[month_index % ce->month_count];
 
     if (month_index >= ce->month_count) {
         out->year = ref->year + 1;
diff --git a/src/cron/expression/c/parse.c b/src/cron/expression/c/parse.c
index b49b5dd..e664dd8 100644
--- a/src/cron/expression/c/parse.c
+++ b/src/cron/expression/c/parse.c
@@ -80,10 +80,10 @@ enum cron_parse_error ce_parse_range(uint64_t *out, char *s, uint8_t min, uint8_
 
     // Single number doesn't need to loop
     if (end == 0 && slash_index == 0) {
-        *out |= 1 << (start - min);
+        *out |= ((uint64_t) 1) << (start - min);
     } else {
         for (;start <= end; start += interval) {
-            *out |= 1 << (start - min);
+            *out |= ((uint64_t) 1) << (start - min);
             start += interval;
         }
     }
@@ -109,13 +109,7 @@ enum cron_parse_error ce_parse_part(uint64_t *out, char *s, uint8_t min, uint8_t
     }
 
     // Make sure to parse the final range as well
-    res = ce_parse_range(out, s, min, max);
-
-    if (res != CPEParseOk) {
-        return res;
-    }
-
-    return CPEParseOk;
+    return ce_parse_range(out, s, min, max);
 }
 
 uint8_t bf_to_nums(uint8_t **out, uint64_t bf, uint8_t min, uint8_t max) {
@@ -125,7 +119,7 @@ uint8_t bf_to_nums(uint8_t **out, uint64_t bf, uint8_t min, uint8_t max) {
     uint8_t *buf = malloc(capacity * sizeof(uint8_t));
 
     for (uint8_t i = 0; i <= max - min; i++) {
-        if ((1 << i) & bf) {
+        if (((uint64_t) 1 << i) & bf) {
             // Resize buffer if needed
             if (size == capacity) {
                 capacity *= 2;
@@ -150,11 +144,12 @@ uint8_t bf_to_nums(uint8_t **out, uint64_t bf, uint8_t min, uint8_t max) {
 enum cron_parse_error ce_parse_expression(struct cron_expression *out, char *s) {
     // The parsing functions modify the input string in-place
     s = strdup(s);
+    char *orig_s = s;
 
     uint8_t part_count = 0;
 
     char *next;
-    enum cron_parse_error res;
+    enum cron_parse_error res = CPEParseOk;
     uint64_t bfs[4];
 
     // Skip leading spaces
@@ -167,10 +162,9 @@ enum cron_parse_error ce_parse_expression(struct cron_expression *out, char *s)
         res = ce_parse_part(&bfs[part_count], s, min[part_count], max[part_count]);
 
         if (res != CPEParseOk) {
-            return res;
+            goto end;
         }
 
-        s = next + 1;
         size_t offset = 1;
 
         // Skip multiple spaces
@@ -188,7 +182,7 @@ enum cron_parse_error ce_parse_expression(struct cron_expression *out, char *s)
         res = ce_parse_part(&bfs[part_count], s, min[part_count], max[part_count]);
 
         if (res != CPEParseOk) {
-            return res;
+            goto end;
         }
 
         part_count++;
@@ -196,7 +190,8 @@ enum cron_parse_error ce_parse_expression(struct cron_expression *out, char *s)
 
     // At least two parts need to be provided
     if (part_count < 2) {
-        return CPEParseInvalidExpression;
+        res = CPEParseInvalidExpression;
+        goto end;
     }
 
     // Ensure there's always 4 parts, as expressions can have between 2 and 4 parts
@@ -211,5 +206,9 @@ enum cron_parse_error ce_parse_expression(struct cron_expression *out, char *s)
     out->day_count = bf_to_nums(&out->days, bfs[2], min[2], max[2]);
     out->month_count = bf_to_nums(&out->months, bfs[3], min[3], max[3]);
 
-    return CPEParseOk;
+end:
+    // s is cloned
+    free(orig_s);
+
+    return res;
 }