diff --git a/src/MonthSelect.php b/src/MonthSelect.php
index 555e491e..19bc1ec5 100644
--- a/src/MonthSelect.php
+++ b/src/MonthSelect.php
@@ -4,11 +4,12 @@
 
 namespace Laminas\Filter;
 
-use function array_reduce;
-use function count;
+use function filter_var;
 use function is_array;
-use function ksort;
-use function vsprintf;
+use function is_numeric;
+use function sprintf;
+
+use const FILTER_VALIDATE_INT;
 
 /**
  * @psalm-type Options = array{
@@ -16,19 +17,18 @@
  *     null_on_all_empty?: bool,
  * }
  * @psalm-type InputArray = array{
- *       year: numeric,
- *       month: numeric,
+ *       year: int,
+ *       month: int,
  *  }
  * @template TInput of array<array-key, numeric>
- * @implements FilterInterface<InputArray|string>
+ * @implements FilterInterface<string>
  */
 final class MonthSelect implements FilterInterface
 {
     private readonly bool $returnNullIfAnyFieldEmpty;
     private readonly bool $returnNullIfAllFieldsEmpty;
-    private const EXPECTED_INPUTS = 2;
 
-    /** Options $options */
+    /** @param Options $options */
     public function __construct(array $options = [])
     {
         $this->returnNullIfAnyFieldEmpty  = $options['null_on_empty'] ?? false;
@@ -40,44 +40,48 @@ public function __invoke(mixed $value): mixed
         return $this->filter($value);
     }
 
-    /**
-     * @psalm-return ($value is InputArray ? string : mixed|null)
-     */
+    /** @psalm-suppress InvalidReturnType */
     public function filter(mixed $value): mixed
     {
         if (! is_array($value)) {
             return $value;
         }
 
-        if (count($value) !== self::EXPECTED_INPUTS) {
-            return $value;
-        }
+        /** @var mixed $month */
+        $month = $value['month'] ?? null;
+        /** @var mixed $year */
+        $year = $value['year'] ?? null;
 
-        // Convert the date to a specific format
-        if (
-            $this->returnNullIfAnyFieldEmpty
-            && array_reduce($value, self::reduce(...), false)
-        ) {
+        if ($this->returnNullIfAnyFieldEmpty && ($month === null || $year === null)) {
             return null;
         }
 
-        if (
-            $this->returnNullIfAllFieldsEmpty
-            && array_reduce($value, self::reduce(...), true)
-        ) {
+        if ($this->returnNullIfAllFieldsEmpty && $month === null && $year === null) {
             return null;
         }
 
-        ksort($value);
-
-
-        /** @psalm-var array<array-key, string> $value Forcing the type here because it has already been asserted */
+        if (! $this->isParsableAsDateValue($month, 1, 12) || ! $this->isParsableAsDateValue($year, 0, 9999)) {
+            /** @psalm-suppress InvalidReturnStatement */
+            return $value;
+        }
 
-        return vsprintf('%2$s-%1$s', $value);
+        /** @psalm-suppress MixedArgument */
+        return sprintf('%s-%s', $year, $month);
     }
 
-    private static function reduce(bool $soFar, string|null $value): bool
+    private function isParsableAsDateValue(mixed $value, int $lowestValue, int $highestValue): bool
     {
-        return $soFar || ($value === null || $value === '');
+        if (
+            ! is_numeric($value)
+            || filter_var(
+                $value,
+                FILTER_VALIDATE_INT,
+                ['options' => ['min_range' => $lowestValue, 'max_range' => $highestValue]]
+            ) === false
+        ) {
+            return false;
+        }
+
+        return true;
     }
 }
diff --git a/test/MonthSelectTest.php b/test/MonthSelectTest.php
index 82251975..ff2889d2 100644
--- a/test/MonthSelectTest.php
+++ b/test/MonthSelectTest.php
@@ -13,6 +13,7 @@ class MonthSelectTest extends TestCase
     #[DataProvider('provideFilter')]
     public function testFilter(array $options, array $input, ?string $expected): void
     {
+        /** @psalm-suppress MixedArgumentTypeCoercion */
         $sut = new MonthSelectFilter($options);
         self::assertSame($expected, $sut->filter($input));
     }
@@ -22,11 +23,12 @@ public static function provideFilter(): array
     {
         return [
             [[], ['year' => '2014', 'month' => '10'], '2014-10'],
-            [[], ['year' => '2014', 'month' => '48'], '2014-48'],
-            [[], ['year' => 'not a year', 'month' => '10'], 'not a year-10'],
-            [[], ['year' => '2023', 'month' => 'not a month'], '2023-not a month'],
+            [[], ['year' => 2014, 'month' => 10], '2014-10'],
             [['null_on_empty' => true], ['year' => null, 'month' => '10'], null],
+            [['null_on_empty' => true], ['month' => null], null],
+            [['null_on_empty' => true], ['year' => null], null],
             [['null_on_all_empty' => true], ['year' => null, 'month' => null], null],
+            [['null_on_all_empty' => true], [], null],
         ];
     }
 
@@ -41,13 +43,21 @@ public function testInvalidInput(mixed $value): void
     public static function provideInvalidFilterValues(): array
     {
         return [
-            [[]],
-            [['month' => '10']],
-            [['year' => '2023']],
-            [true],
-            ['string'],
-            [10],
-            [10.5],
+            'empty array'           => [[]],
+            'missing year'          => [['month' => '10']],
+            'missing month'         => [['year' => '2023']],
+            'passed bool'           => [true],
+            'passed string'         => ['string'],
+            'passed int'            => [10],
+            'passed float'          => [10.5],
+            'invalid keys'          => [['should be year' => '2014', 'should be month' => '10']],
+            'year is invalid type'  => [['year' => true, 'month' => '09']],
+            'year out of bounds'    => [['year' => '-1', 'month' => '09']],
+            'month is too high'     => [['year' => '2014', 'month' => '13']],
+            'month is low'          => [['year' => '2014', 'month' => '0']],
+            'month is invalid type' => [['year' => '2014', 'month' => true]],
+            'invalid year'          => [['year' => 'not a year', 'month' => '10']],
+            'invalid month'         => [['year' => '2023', 'month' => 'not a month']],
         ];
     }
 }