diff --git a/web/src/main/java/org/springframework/security/web/authentication/preauth/x509/SubjectDnX509PrincipalExtractor.java b/web/src/main/java/org/springframework/security/web/authentication/preauth/x509/SubjectDnX509PrincipalExtractor.java
index 18693d5533..6a667e5de7 100644
--- a/web/src/main/java/org/springframework/security/web/authentication/preauth/x509/SubjectDnX509PrincipalExtractor.java
+++ b/web/src/main/java/org/springframework/security/web/authentication/preauth/x509/SubjectDnX509PrincipalExtractor.java
@@ -36,7 +36,7 @@ import java.util.regex.Matcher;
  * expression "CN=(.*?)(?:,|$)" matches the common name field. So
  * "CN=Jimi Hendrix, OU=..." will give a user name of "Jimi Hendrix".
  * <p>
- * The matches are case insensitive. So "emailAddress=(.?)," will match
+ * The matches are case insensitive. So "emailAddress=(.*?)," will match
  * "EMAILADDRESS=jimi@hendrix.org, CN=..." giving a user name "jimi@hendrix.org"
  *
  * @author Luke Taylor