diff --git a/docs/index.asciidoc b/docs/index.asciidoc
index a8743aab8..d3eb8943b 100644
--- a/docs/index.asciidoc
+++ b/docs/index.asciidoc
@@ -333,7 +333,7 @@ this defaults to a concatenation of the path parameter and "_bulk"
   * Value type is <<path,path>>
   * There is no default value for this setting.
 
-The .cer or .pem file to validate the server's certificate
+The .cer or .crt file to validate the server's certificate
 
 [id="plugins-{type}s-{plugin}-cloud_auth"]
 ===== `cloud_auth`
diff --git a/lib/logstash/outputs/elasticsearch.rb b/lib/logstash/outputs/elasticsearch.rb
index 5639bad3a..6c4d58e6b 100644
--- a/lib/logstash/outputs/elasticsearch.rb
+++ b/lib/logstash/outputs/elasticsearch.rb
@@ -156,7 +156,7 @@ class LogStash::Outputs::ElasticSearch < LogStash::Outputs::Base
   # https://www.cs.utexas.edu/~shmat/shmat_ccs12.pdf
   config :ssl_certificate_verification, :validate => :boolean, :default => true
 
-  # The .cer or .pem file to validate the server's certificate
+  # The .cer or .crt file to validate the server's certificate
   config :cacert, :validate => :path
 
   # The JKS truststore to validate the server's certificate.