GHSA-3989-4c6x-725f

### Impact
Any user with view rights on `XWiki.AttachmentSelector` can execute arbitrary Groovy, Python or Velocity code in XWiki leading to full access to the XWiki installation. The root cause is improper escaping in the "Cancel and return to page" button. This page is installed by default.

See https://jira.xwiki.org/browse/XWIKI-20275 for the reproduction steps.

### Patches
The vulnerability has been patched in XWiki 15.0-rc-1, 14.10.1, 14.4.8, and 13.10.11.

### Workarounds
The issue can be fixed by applying this [patch](https://github.com/xwiki/xwiki-platform/commit/aca1d677c58563bbe6e35c9e1c29fd8b12ebb996) on `XWiki.AttachmentSelector`.

### References
- https://github.com/xwiki/xwiki-platform/commit/aca1d677c58563bbe6e35c9e1c29fd8b12ebb996
- https://jira.xwiki.org/browse/XWIKI-20275

### For more information

If you have any questions or comments about this advisory:

* Open an issue in [Jira XWiki.org](https://jira.xwiki.org/)
* Email us at [Security Mailing List](mailto:[email protected])