CVE-2026-23986: Copier-Org Copier

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

Copier is a library and CLI app for rendering project templates. Prior to version 9.11.2, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the `--UNSAFE,--trust` flag. As it turns out, a safe template can currently write to arbitrary directories outside the destination path by using directory a symlink along with `_preserve_symlinks: true` and a generated directory structure whose rendered path is inside the symlinked directory. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. Version 9.11.2 patches the issue.

Affected products

• Copier-Org Copier: before 9.11.2 (fixed in 9.11.2)

Published 2026-01-21. Last modified 2026-06-17.