CVE-2025-55201 Copier safe template has arbitrary filesystem read/write access
Attackers can read and write arbitrary files via exposed pathlib objects in Jinja context, bypassing filesystem security controls.
- 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-2025-55201?
CVE-2025-55201 is a high-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. Prior to 9.9.1, a safe template can currently read and write arbitrary files because Copier exposes a few pathlib.Path objects in the Jinja context which have unconstrained I/O methods. This effectively renders the security model w.r.t. filesystem access useless. This vulnerability is fixed in 9.9.1.
Weakness: CWE-22
Which versions are affected by CVE-2025-55201?
3 open source packages ship an affected version, including copier.
| Package | Affected | Fixed in |
|---|---|---|
copier PyPI | All versions | 9.9.1 |
copier PyPI | All versions | 9.9.1 |
copier PyPI | All versions | 9.9.1 |
How do I fix CVE-2025-55201?
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-2025-55201 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55201 exists.
Sources
Also known as GHSA-3xw7-v6cj-5q8h, PYSEC-2026-1271.