Wagtail has improper permission handling when copying pages
### Impact
A CMS user with limited access to pages could copy a page they don't have access to to an area of the site they do. Once copied, they'd be able to view its contents, and potentially publish it. Permissions were correctly checked for the copy destination, but not for the source page.
### Patches
Patched versions have been released as Wagtail 7.0.7 and 7.3.2. The new 7.4 LTS feature release also incorporates this fix.
### Workarounds
No workaround is available.
### Acknowledgements
Wagtail thanks independent security researcher Sanjok Karki @thesanjok for reporting this issue.
### For more information
If there are any questions or comments about this advisory:
* Visit Wagtail's support channels
https://docs.wagtail.org/en/stable/support.html
* Send an email to [security@wagtail.org](mailto:security@wagtail.org) (view the security policy
https://github.com/wagtail/wagtail/security/policy for more information).