CVE-2026-34730
Medium
Description
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.
SeverityMedium
CVSS5.5
Exploit probability—
ProductCopier
PublishedApr 2, 2026
First seenApr 2, 2026
Weakness typeCWE-22Path traversal
How to fix
Update
- copier-org copier9.14.1 or later
- copier9.14.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| copier-org copier | v < 9.14.1 | 9.14.1 |
| copierPyPI | v < 9.14.1 | 9.14.1 |
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