diff --git a/Zend/zend_ini_parser.y b/Zend/zend_ini_parser.y
index 748ccd2235a6d..e384d320cebfc 100644
--- a/Zend/zend_ini_parser.y
+++ b/Zend/zend_ini_parser.y
@@ -205,7 +205,11 @@ static ZEND_COLD void ini_error(const char *msg)
 		error_buf_len = 128 + (int)strlen(msg) + (int)strlen(currently_parsed_filename); /* should be more than enough */
 		error_buf = (char *) emalloc(error_buf_len);
 
-		sprintf(error_buf, "%s in %s on line %" PRIu32 "\n", msg, currently_parsed_filename, zend_ini_scanner_get_lineno());
+		if (strcmp(currently_parsed_filename, "Unknown") == 0 && CG(ini_parser_unbuffered_errors)) {
+			sprintf(error_buf, "%s in INI command line parameter '-d'\n", msg);
+		} else {
+			sprintf(error_buf, "%s in %s on line %" PRIu32 "\n", msg, currently_parsed_filename, zend_ini_scanner_get_lineno());
+		}
 	} else {
 		error_buf = estrdup("Invalid configuration directive\n");
 	}
diff --git a/sapi/cli/tests/gh20871.phpt b/sapi/cli/tests/gh20871.phpt
new file mode 100644
index 0000000000000..99b825eaae851
--- /dev/null
+++ b/sapi/cli/tests/gh20871.phpt
@@ -0,0 +1,29 @@
+--TEST--
+GH-20871: Bad error line and file for invalid "-d" arguments
+--SKIPIF--
+<?php include "skipif.inc"; ?>
+--FILE--
+<?php
+$php = getenv('TEST_PHP_EXECUTABLE_ESCAPED');
+
+exec("$php -d 'foo=bar=asd' -r \"echo 'hello' . PHP_EOL;\" 2>&1", $output, $exit_code);
+print_r($output);
+
+echo "\n";
+
+exec("$php -d 'foo=bar!asd' -r \"echo 'world' . PHP_EOL;\" 2>&1", $output2, $exit_code2);
+print_r($output2);
+
+?>
+--EXPECTF--
+Array
+(
+    [0] => PHP:  syntax error, unexpected '=' in INI command line parameter '-d'
+    [1] => hello
+)
+
+Array
+(
+    [0] => PHP:  syntax error, unexpected '!' in INI command line parameter '-d'
+    [1] => world
+)