Headline
CVE-2023-26482: Scope of workflow operations is not validated
Nextcloud server is an open source home cloud implementation. In affected versions a missing scope validation allowed users to create workflows which are designed to be only available for administrators. Some workflows are designed to be RCE by invoking defined scripts, in order to generate PDFs, invoking webhooks or running scripts on the server. Due to this combination depending on the available apps the issue can result in a RCE at the end. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should disable app workflow_scripts and workflow_pdf_converter as a mitigation.
Impact
A missing scope validation allowed users to create workflows which are designed to be only available for administrators. Some workflows are designed to be RCE by invoking defined scripts, in order to generate PDFs, invoking webhooks or running scripts on the server. Due to this combination depending on the available apps the issue can result in a RCE at the end.
Patches
It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4
It is recommended that the Nextcloud Enterprise Server is upgraded to 20.0.14.12 or 21.0.9.10 or 22.2.10.10 or 23.0.12.5 or 24.0.10 or 25.0.4
It is recommended that the Nextcloud Enterprise Server 18 or Nextcloud Enterprise Server 19 is manually patched.
Workarounds
- Disable app workflow_scripts and workflow_pdf_converter
References
- HackerOne
For more information
If you have any questions or comments about this advisory:
- Create a post in nextcloud/security-advisories
- Customers: Open a support ticket at support.nextcloud.com