diff --git a/ldap/servers/slapd/str2filter.c b/ldap/servers/slapd/str2filter.c
index 5620b7439f..2733888286 100644
--- a/ldap/servers/slapd/str2filter.c
+++ b/ldap/servers/slapd/str2filter.c
@@ -313,9 +313,12 @@ str2simple(char *str, int unescape_filter)
 
     PR_ASSERT(str);
 
-    if ((s = strchr(str, '=')) == NULL) {
+    if ((s = strchr(str, '=')) == NULL || s == str) {
         return (NULL);
     }
+    if (s[-1] & 0x80) {
+        return NULL;
+    }
     value = s;
     LDAP_UTF8INC(value);
     LDAP_UTF8DEC(s);