medium5.5
CVE-2026-34730
Copier `_external_data` allows path traversal and absolute-path local file read without unsafe mode
Impact
Copier is a library and CLI app for rendering project templates. Prior to version 9.14.1, Copier's _external_data feature allows a template to load YAML files using template-controlled paths. If untrusted templates are in scope, a malicious template can read attacker-chosen YAML-parseable local files that are accessible to the user running Copier and expose their contents in rendered output. This issue has been patched in version 9.14.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | copier | <= 9.14.0 | 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-hgjq-p8cr-gg4h
- https://github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h
- https://nvd.nist.gov/vuln/detail/CVE-2026-34730
- https://github.com/copier-org/copier/commit/5413062eb17b73dc885f5e645cdc161e69ef641b
- https://github.com/copier-org/copier/releases/tag/v9.14.1