diff --git a/CHANGES b/CHANGES
index 7ed7308b70ad0dff6da23c9d52f6f51767906c43..2eb1186921e764e2fab1c37316d228389ea36511 100644
--- a/CHANGES
+++ b/CHANGES
@@ -24,6 +24,7 @@ OpenLDAP 2.4.12 Engineering
 	Fixed slapo-constraint string termination (ITS#5609)
 	Fixed slapo-memberof internal operations DN (ITS#5622)
 	Fixed slapo-pcache attrset crash (ITS#5665)
+	Fixed slapo-pcache caching with invalid schema (ITS#5680)
 	Fixed slapo-rwm callback cleanup (ITS#5601)
 	Fixed slapo-rwm attr mapping and merging (ITS#5624)
 	Fixed slapo-rwm objectClass filtering (ITS#5647)
diff --git a/servers/slapd/overlays/pcache.c b/servers/slapd/overlays/pcache.c
index d73835662f6ef19f95a83e2907bc633721b65e0c..22b8355865071a9f1ba995656a1cb6415b219054 100644
--- a/servers/slapd/overlays/pcache.c
+++ b/servers/slapd/overlays/pcache.c
@@ -1961,6 +1961,14 @@ pcache_op_cleanup( Operation *op, SlapReply *rs ) {
 		 * limit, empty the chain and ignore the rest.
 		 */
 		if ( !si->over ) {
+			/* check if the entry contains undefined
+			 * attributes/objectClasses (ITS#5680) */
+			if ( test_filter( op, rs->sr_entry, si->query.filter ) != LDAP_COMPARE_TRUE ) {
+				Debug( pcache_debug, "%s: query not cacheable because of schema issues in DN \"%s\"\n",
+					op->o_log_prefix, rs->sr_entry->e_name.bv_val, 0 );
+				goto over;
+			}
+
 			if ( si->count < si->max ) {
 				si->count++;
 				e = entry_dup( rs->sr_entry );
@@ -1969,6 +1977,7 @@ pcache_op_cleanup( Operation *op, SlapReply *rs ) {
 				si->tail = e;
 
 			} else {
+over:;
 				si->over = 1;
 				si->count = 0;
 				for (;si->head; si->head=e) {