AIKIDO-2026-410875
copier is vulnerable to Path Traversal
55
Medium Risk
This Affects:
copierTL;DR
Copier processes templates using a YAML !include tag that expands glob patterns to load additional configuration files. The tag only rejects absolute paths and does not confirm the resolved path stays within the template root, so a .. segment in a glob pattern reaches files outside the template directory. Processing an untrusted template with copier copy or copier update can disclose local files such as .copier-answers.yml, tokens, and other secrets. The fix resolves !include paths and raises ForbiddenPathError for paths outside the template root.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you run copier against an untrusted template that uses the YAML !include tag.
Background info
copier is vulnerable to Path Traversal in versions 9.1.0 - 9.17.1.
How to fix this
Upgrade the copier library to the patch version.
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SOC 2Compliant
ISO 27001Compliant