Fix handling of some conditional comment tags in HTML message (#1489004)

Conflicts:

	CHANGELOG

2 files changed, 3 insertions, 1 deletions

diff --git a/CHANGELOG b/CHANGELOG
index e8e664b4f..ab110bb95 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix handling of some conditional comment tags in HTML message (#1489004)
 - Fix so forward as attachment works if additional attachment is added by message_compose hook (#1489000)
 - Better handling of session errors in ajax requests (#1488960)
 - Fix HTML part detection for some specific message structures (#1488992)
diff --git a/program/lib/Roundcube/rcube_washtml.php b/program/lib/Roundcube/rcube_washtml.php
index 2a261419f..27dff9f48 100644
--- a/program/lib/Roundcube/rcube_washtml.php
+++ b/program/lib/Roundcube/rcube_washtml.php
@@ -413,7 +413,8 @@ class rcube_washtml
 
         // Remove invalid HTML comments (#1487759)
         // Don't remove valid conditional comments
-        $html = preg_replace('/<!--[^->[\n]*>/', '', $html);
+        // Don't remove MSOutlook (<!-->) conditional comments (#1489004)
+        $html = preg_replace('/<!--[^->\[\n]+>/', '', $html);
 
         // turn relative into absolute urls
         $html = self::resolve_base($html);