diff --git a/doc/security.mdwn b/doc/security.mdwn
index 4fa531eb1..e636a0e45 100644
--- a/doc/security.mdwn
+++ b/doc/security.mdwn
@@ -453,3 +453,12 @@ preview or moderation of comments with such a configuration.
 
 These problems were discovered on 12 November 2010 and fixed the same
 hour with the release of ikiwiki 3.20101112. ([[!cve CVE-2010-1673]])
+
+## javascript insertation via insufficient checking in comments
+
+Dave B noticed that attempting to comment on an illegal page name could be
+used for an XSS attack.
+
+This hole was discovered on 22 Jan 2011 and fixed the same day with
+the release of ikiwiki 3.20110122. An upgrade is recommended for sites
+with the comments plugin enabled.