Vulnerability · Published Apr 2, 2026 · Assigned by GitHub_M
CVE-2026-34730Copier `_external_data` allows path traversal and absolute-path local file read without unsafe mode
Medium 5.5
In plain English
A medium-severity path traversal in copier from copier-org. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | copier | 9.14.1 | GHSA-hgjq-p8cr-gg4h |
| PyPI | copier | 9.14.1 | PYSEC-2026-2135 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| copier-org | copier | < 9.14.1 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N