diff --git a/NEWS b/NEWS
index cbf9dd7bd79..805363ed248 100644
--- a/NEWS
+++ b/NEWS
@@ -39,6 +39,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-17984 (calls with arguments as array with references).
     (David Carlier)
 
+- LDAP:
+  . Fixed bug GH-18015 (Error messages for ldap_mod_replace are confusing).
+    (nielsdos)
+
 - Mbstring:
   . Fixed bug GH-17989 (mb_output_handler crash with unset
     http_output_conv_mimetypes). (nielsdos)
diff --git a/ext/ldap/ldap.c b/ext/ldap/ldap.c
index 67b01c0ec44..20245ed5696 100644
--- a/ext/ldap/ldap.c
+++ b/ext/ldap/ldap.c
@@ -2278,7 +2278,7 @@ static void php_ldap_do_modify(INTERNAL_FUNCTION_PARAMETERS, int oper, int ext)
 			ldap_mods[i]->mod_bvalues[0]->bv_len = Z_STRLEN_P(value);
 		} else {
 			if (!php_ldap_is_numerically_indexed_array(Z_ARRVAL_P(value))) {
-				zend_argument_value_error(3, "must be an array with numeric keys");
+				zend_argument_value_error(3, "attribute \"%s\" must be an array with numeric keys", ZSTR_VAL(attribute));
 				RETVAL_FALSE;
 				num_berval[i] = 0;
 				num_attribs = i + 1;
diff --git a/ext/ldap/tests/ldap_add_error.phpt b/ext/ldap/tests/ldap_add_error.phpt
index 5036b3091e8..209a7fb165d 100644
--- a/ext/ldap/tests/ldap_add_error.phpt
+++ b/ext/ldap/tests/ldap_add_error.phpt
@@ -104,7 +104,7 @@ Warning: ldap_add(): Add: Already exists in %s on line %d
 bool(false)
 string(14) "Already exists"
 int(68)
-ldap_add(): Argument #3 ($entry) must be an array with numeric keys
+ldap_add(): Argument #3 ($entry) attribute "objectClass" must be an array with numeric keys
 
 Warning: ldap_add(): Add: Undefined attribute type in %s on line %d
 bool(false)