Vulnerability Description
Copier library and CLI app for rendering project templates. From 7.1.0 to before 9.9.1, 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 files outside the destination path where a project shall be generated or updated. This is possible when rendering a generated directory structure whose rendered path is either a relative parent path or an absolute path. Constructing such paths is possible using Copier's builtin pathjoin Jinja filter and its builtin _copier_conf.sep variable, which is the platform-native path separator. 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. This vulnerability is fixed in 9.9.1.
Related Weaknesses (CWE)
References
- https://github.com/copier-org/copier/commit/fdbc0167cc22780b497e4db176feaf6f0247
- https://github.com/copier-org/copier/security/advisories/GHSA-p7q8-grrj-3m8w
FAQ
What is CVE-2025-55214?
CVE-2025-55214 is a documented vulnerability. Copier library and CLI app for rendering project templates. From 7.1.0 to before 9.9.1, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe feat...
How severe is CVE-2025-55214?
CVSS scoring is not yet available for CVE-2025-55214. Check NVD for updates.
Is there a patch for CVE-2025-55214?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.