Problem

Pages fail to load in GUI with EmptyStackException in AntiSamy CDATA parsing

Steps to Reproduce

1. Create an empty Confluence page
2. Set the below body in the bodycontent table for the page created at 1.

   <h3>Section</h3>
   <p>Some contnet.<br />
       <ac:emoticon ac:name="warning" /> Some more content
   </p>
   <p>placeholder...</p>
   <p>placeholder</p>
   <h3>placeholder</h3>
   <p>placeholder:
       <code>putKeyValue = function(key, value, <ac:link><ri:page ri:content-title="okCallback, errCallback" ri:space-key="TEST" /><ac:plain-text-link-body><![CDATA[okCallback, errCallback]]></ac:plain-text-link-body></ac:link>)</code>
   </p>
   <ac:parameter ac:name="title">placeholder</ac:parameter>
   <ac:parameter ac:name="language">javascript</ac:parameter><ac:plain-text-body>
       <![CDATA[kvs.putKeyValue("key", "value");
   ]]>
   </ac:plain-text-body>
   <h3>placeholder</h3>
   <p>placeholder</p>
   <p>placeholder
       <code>getKeyValue = function(key, dataCallback, <ac:link><ri:page ri:content-title="errCallback" ri:space-key="TEST" /><ac:plain-text-link-body><![CDATA[errCallback]]></ac:plain-text-link-body></ac:link>)</code>
   </p>
   <ac:parameter ac:name="title">placeholder</ac:parameter>
   <ac:parameter ac:name="language">javascript</ac:parameter><ac:plain-text-body>
       <![CDATA[// define the data callback
   var dataCallback = function(valuestring) {
       //work with valuestring
   };// get the value 
   kvs.getKeyValue("key", dataCallback);
   ]]>
   </ac:plain-text-body>  

1. Flush Confluence cache
2. Attempt to view the page

Expected Results

Page should be visible.

Actual Results

The export fails and the following message is found in the logs:

2026-03-12 11:32:26,004 ERROR [http-nio-21027-exec-6 url: /c1027/500page.jsp; user: admin] [atlassian.confluence.status.SystemErrorInformationLogger] logException Unhandled exception, request unique ID: 24c144f7-ad7b-49a1-a9c1-0aec26474dda -- traceId: c393fe629cbb7b39java.lang.RuntimeException: org.owasp.validator.html.ScanException: java.util.EmptyStackException
...
Caused by: org.owasp.validator.html.ScanException: java.util.EmptyStackException
...
Caused by: java.util.EmptyStackException

The above failure is caused by the following block in the storage format:

<ac:parameter ac:name="language">javascript</ac:parameter><ac:plain-text-body>
    <![CDATA[// define the data callback
var dataCallback = function(valuestring) {
    //work with valuestring
};// get the value 
kvs.getKeyValue("key", dataCallback);
]]>
</ac:plain-text-body>

as the antiSamyClean code is removing the content from the CDATA element and causes the EmptyStackException.

Workaround

Change the problematic entry in the body content of the page from:

<ac:parameter ac:name="language">javascript</ac:parameter><ac:plain-text-body>
    <![CDATA[// define the data callback
var dataCallback = function(valuestring) {
    //work with valuestring
};// get the value 
kvs.getKeyValue("key", dataCallback);
]]>
</ac:plain-text-body>

to

<ac:parameter ac:name="language">javascript</ac:parameter><ac:plain-text-body>
 <code>
    <![CDATA[// define the data callback
var dataCallback = function(valuestring) {
    //work with valuestring
};// get the value 
kvs.getKeyValue("key", dataCallback);
]]>
 </code>
</ac:plain-text-body>

You can update the page directly in the database using a query like this:

UPDATE BODYCONTENT
SET BODY = REGEXP_REPLACE(
    BODY,
    '<ac:plain-text-body><!\[CDATA\[.*?\]\]></ac:plain-text-body>',
    '',
    'gs'
)
WHERE contentid IN ('1212423','1212419'); 

Change the contentid in the where clause to match the page's content ID you need to fix.

Please remember to take a backup of your database and Confluence environment before making any changes and test on a staging server first.