diff --git a/src/common/impl/option.c b/src/common/impl/option.c
index a6dc09673..7390f7b66 100644
--- a/src/common/impl/option.c
+++ b/src/common/impl/option.c
@@ -3,8 +3,12 @@
 #include "common/color.h"
 #include "common/stringUtils.h"
 
+#include <limits.h>
+
 // Return start position of the inner key if the argument key belongs to the module specified, NULL otherwise
 const char* ffOptionTestPrefix(const char* argumentKey, const char* moduleName) {
+    assert(argumentKey && moduleName);
+
     const char* subKey = argumentKey;
     if (!(subKey[0] == '-' && subKey[1] == '-')) {
         return NULL;
@@ -47,13 +51,13 @@ uint32_t ffOptionParseUInt32(const char* argumentKey, const char* value) {
     }
 
     char* end;
-    uint32_t num = (uint32_t) strtoul(value, &end, 10);
-    if (*end != '\0') {
+    unsigned long num = strtoul(value, &end, 10);
+    if (value[0] == '-' || *end != '\0' || num > UINT32_MAX) {
         fprintf(stderr, "Error: usage: %s <num>\n", argumentKey);
         exit(479);
     }
 
-    return num;
+    return (uint32_t) num;
 }
 
 int32_t ffOptionParseInt32(const char* argumentKey, const char* value) {
@@ -63,13 +67,13 @@ int32_t ffOptionParseInt32(const char* argumentKey, const char* value) {
     }
 
     char* end;
-    int32_t num = (int32_t) strtol(value, &end, 10);
-    if (*end != '\0') {
+    long num = strtol(value, &end, 10);
+    if (*end != '\0' || num < INT32_MIN || num > INT32_MAX) {
         fprintf(stderr, "Error: usage: %s <num>\n", argumentKey);
         exit(479);
     }
 
-    return num;
+    return (int32_t) num;
 }
 
 int ffOptionParseEnum(const char* argumentKey, const char* requestedKey, FFKeyValuePair pairs[]) {