medium4.4
CVE-2026-34726
Copier `_subdirectory` allows template root escape via parent-directory traversal
Impact
Copier is a library and CLI app for rendering project templates. Prior to version 9.14.1, Copier's _subdirectory setting is documented as the subdirectory to use as the template root. However, the current implementation accepts parent-directory traversal such as .. and uses it directly when selecting the template root. As a result, a template can escape its own directory and make Copier render files from the parent directory without --UNSAFE. This issue has been patched in version 9.14.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | copier | < 9.14.1 | 9.14.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Copier-Org | Copier | before 9.14.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-85v3-4m8g-hrh6
- https://github.com/copier-org/copier/security/advisories/GHSA-85v3-4m8g-hrh6
- https://nvd.nist.gov/vuln/detail/CVE-2026-34726
- https://github.com/copier-org/copier/commit/cb80a3ffc9c3787de3ed837e04ca29a0ff8ca3df
- https://github.com/copier-org/copier/releases/tag/v9.14.1