diff --git a/ext/posix/posix.c b/ext/posix/posix.c
index f6e028f9a96e3..787b18ae28126 100644
--- a/ext/posix/posix.c
+++ b/ext/posix/posix.c
@@ -521,11 +521,13 @@ PHP_FUNCTION(posix_isatty)
 
 	/* A valid file descriptor must fit in an int and be positive */
 	if (fd < 0 || fd > INT_MAX) {
+		POSIX_G(last_error) = EBADF;
 		RETURN_FALSE;
 	}
 	if (isatty(fd)) {
 		RETURN_TRUE;
 	} else {
+		POSIX_G(last_error) = errno;
 		RETURN_FALSE;
 	}
 }
diff --git a/ext/posix/tests/posix_isatty_value_errors.phpt b/ext/posix/tests/posix_isatty_value_errors.phpt
index 19dfe62c93019..e57564e7eacd7 100644
--- a/ext/posix/tests/posix_isatty_value_errors.phpt
+++ b/ext/posix/tests/posix_isatty_value_errors.phpt
@@ -11,13 +11,19 @@ if (PHP_INT_SIZE != 8) die('skip C int is same size as zend_long');
 
 $values = [
     -1,
+    10024,
     2**50+1,
 ];
 
 foreach ($values as $value) {
     var_dump(posix_isatty($value));
+    var_dump(posix_strerror(posix_get_last_error()));
 }
 ?>
 --EXPECT--
 bool(false)
+string(19) "Bad file descriptor"
 bool(false)
+string(19) "Bad file descriptor"
+bool(false)
+string(19) "Bad file descriptor"