Bookstack · Bookstack · CVE-2020-11055
**Name of the Vulnerable Software and Affected Versions**
BookStack versions 0.18.0 through 0.29.1
**Description**
The issue allows a user with permission to create comments to inject custom JavaScript code, which could be executed on other users' machines. This is particularly impactful in scenarios where untrusted users have comment creation permissions. The vulnerability arises from the ability to POST HTML directly to the system, which is then saved and displayed to other users.
**Recommendations**
For BookStack versions 0.18.0 through 0.29.1, update to version 0.29.2 to address the issue. After upgrading, run the command `php artisan bookstack:regenerate-comment-content` to remove any pre-existing dangerous content. As a temporary workaround, consider disabling comments in the system settings or altering comment creation permissions to only trusted users. However, note that altering permissions will not address existing exploitation of this vulnerability.