diff --git a/NEWS b/NEWS
index 5f7017b6368..c2e1c14bc73 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-17703 (imagescale with both width and height negative values
     triggers only an Exception on width). (David Carlier)
 
+- LDAP:
+  . Fixed bug GH-17704 (ldap_search fails when $attributes contains a
+    non-packed array with numerical keys). (nielsdos, 7u83)
+
 - MBString:
   . Fixed bug GH-17503 (Undefined float conversion in mb_convert_variables).
     (cmb)
diff --git a/ext/ldap/ldap.c b/ext/ldap/ldap.c
index ad112a968f2..67b01c0ec44 100644
--- a/ext/ldap/ldap.c
+++ b/ext/ldap/ldap.c
@@ -247,7 +247,7 @@ static bool php_ldap_is_numerically_indexed_array(zend_array *arr)
 		}
 	} ZEND_HASH_FOREACH_END();
 
-	return false;
+	return true;
 }
 
 /* {{{ Parse controls from and to arrays */
diff --git a/ext/ldap/tests/gh17704.phpt b/ext/ldap/tests/gh17704.phpt
new file mode 100644
index 00000000000..2403a63860e
--- /dev/null
+++ b/ext/ldap/tests/gh17704.phpt
@@ -0,0 +1,24 @@
+--TEST--
+GH-17704 (ldap_search fails when $attributes contains a non-packed array with numerical keys)
+--EXTENSIONS--
+ldap
+--SKIPIF--
+<?php
+require_once('skipifbindfailure.inc');
+?>
+--FILE--
+<?php
+include "connect.inc";
+
+$link = ldap_connect_and_bind($uri, $user, $passwd, $protocol_version);
+
+$attributes = ["uid", "cn"];
+// force a non-packed array
+$attributes["x"] = "x";
+unset($attributes["x"]);
+
+var_dump(ldap_search($link, $base, "(o=*)", $attributes));
+?>
+--EXPECTF--
+object(LDAP\Result)#%d (0) {
+}