CVE-2026-27819: 
vulnerability analysis and mitigation

Vikunja is an open-source self-hosted task management platform. Prior to version 2.0.0, the restoreConfig function in vikunja/pkg/modules/dump/restore.go of the go-vikunja/vikunja repository fails to sanitize file paths within the provided ZIP archive. A maliciously crafted ZIP can bypass the intended extraction directory to overwrite arbitrary files on the host system. Additionally, we’ve discovered that a malformed archive triggers a runtime panic, crashing the process immediately after the database has been wiped permanently. The application trusts the metadata in the ZIP archive. It uses the Name attribute of the zip.File struct directly in os.OpenFile calls without validation, allowing files to be written outside the intended directory. The restoration logic assumes a specific directory structure within the ZIP. When provided with a "minimalist" malicious ZIP, the application fails to validate the length of slices derived from the archive contents. Specifically, at line 154, the code attempts to access an index of len(ms)-2 on an insufficiently populated slice, triggering a panic. Version 2.0.0 fixes the issue.