diff --git a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/saml/SamlAuthenticator.java b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/saml/SamlAuthenticator.java
index 0ddc1054de9c2..77fe28f870145 100644
--- a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/saml/SamlAuthenticator.java
+++ b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/saml/SamlAuthenticator.java
@@ -68,7 +68,8 @@ SamlAttributes authenticate(SamlToken token) {
             try {
                 return authenticateResponse(root, token.getAllowedSamlRequestIds());
             } catch (ElasticsearchSecurityException e) {
-                logger.trace("Rejecting SAML response {} because {}", SamlUtils.toString(root), e.getMessage());
+                logger.trace("Rejecting SAML response [{}...] because {}", Strings.cleanTruncate(SamlUtils.toString(root), 512),
+                    e.getMessage());
                 throw e;
             }
         } else {