CVE-2025-55214 Copier safe template has filesystem write access outside destination path
A malicious template can write files outside the destination directory, allowing arbitrary file overwrites via path traversal in Copier.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-55214?
CVE-2025-55214 is a medium-severity path traversal vulnerability in copier-org copier, published on 18 Aug 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-22
Which versions are affected by CVE-2025-55214?
3 open source packages ship an affected version, including copier.
| Package | Affected | Fixed in |
|---|---|---|
copier PyPI | From 7.1.0 | 9.9.1 |
copier PyPI | From 7.1.0 | 9.9.1 |
copier PyPI | From 7.1.0 | 9.9.1 |
How do I fix CVE-2025-55214?
Upgrade copier to 9.9.1 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2025-55214 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55214 exists.
Sources
Also known as GHSA-p7q8-grrj-3m8w, PYSEC-2026-1273.