CVE-2026-34730
Copier `_external_data` allows path traversal and absolute-path local file read without unsafe mode
MEDIUM 5.5EPSS 0.2%
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
- copier-org · copier
- CVSS v3.1 GITHUB
- 5.5 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - EPSS
- 0.21% chance of exploitation in the next 30 days, 10th percentile
- Published
- 2026-04-02
- Updated
- 2026-04-03
Proof-of-concept exploits (1)
Security advisories
- copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h
- copier-org/copier/commit/5413062eb17b73dc885f5e645cdc161e69ef641b