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 products
copier-org: copier
References4
- github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr… ExploitVendor Advisory
- github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr… ExploitVendor Advisory
- github.com/copier-org/copier/commit/5413062eb17b73dc885f5e645cd… Patch
- github.com/copier-org/copier/releases/tag/v9.14.1 Release Notes
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 23 · as of 12 November 2026
- CWE
- CWE-22
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.