CVE-2026-63270: Environment/ini-file leaks
URLs could be constructed which expanded environment variable or INI file values, so potentially sensitive information could be exfiltrated to a remote server on opening a document containing such links. The check added for CVE-2024-12426 did not cover every place a document can supply a URL. XForms instance data and the Calc csv and sql data providers still reached the expansion. In fixed versions these places refuse URLs with internal schemes when the URL comes from the document.
Affected Software
Event History
Frequently Asked Questions
Which document features can trigger the information leak?
The affected URL paths are XForms instance data and Calc CSV and SQL data providers. A document-supplied URL in those locations could expand environment-variable or INI-file values.
What must an attacker do to exploit this issue?
An attacker must craft a document containing a malicious link or URL in an affected feature and persuade a user to open it. The expanded value could then be exfiltrated to a remote server.
What behavior changes in fixed versions?
Fixed versions refuse document-supplied URLs using internal schemes in the affected locations. This prevents those URLs from reaching environment-variable or INI-file expansion.