CVE-2025-66438: Code Injection

A Server-Side Template Injection (SSTI) vulnerability exists in the Frappe ERPNext through 15.89.0 Print Format rendering mechanism. Specifically, the API frappe.www.printview.gethtmlandstyle() triggers the rendering of the html field inside a Print Format document using frappe.rendertemplate(template, doc) via the getrenderedtemplate() call chain. Although ERPNext wraps Jinja2 in a SandboxedEnvironment, it exposes sensitive functions such as frappe.db.sql through getsafeglobals(). An authenticated attacker with permission to create or modify a Print Format can inject arbitrary Jinja expressions into the html field. Once the malicious Print Format is saved, the attacker can call gethtmlandstyle() with a target document (e.g., Supplier or Sales Invoice) to trigger the render process. This leads to information disclosure from the database, such as database version, schema details, or sensitive values, depending on the injected payload. Exploitation flow: Create a Print Format with SSTI payload in the html field; call the gethtmlandstyle() API; triggers frappe.rendertemplate(template, doc) inside getrenderedtemplate(); leaks database information via frappe.db.sql or other exposed globals.