What’s Vulnerable › Vulnerabilities

CVE-2026-23968: Copier safe template has arbitrary filesystem read access via symlinks when _preserve_symlinks: false

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-21 · updated 2026-06-17
• Weakness: CWE-61

Description

Copier is a library and CLI app for rendering project templates. Prior to version 9.11.2, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the `--UNSAFE,--trust` flag. As it turns out, a safe template can currently include arbitrary files/directories outside the local template clone location by using symlinks along with `_preserve_symlinks: false` (which is Copier's default setting). Version 9.11.2 patches the issue.

Affected products

• copier-org copier: before 9.11.2 — fixed in 9.11.2

How to fix

Upgrade to a fixed version: copier-org copier 9.11.2. Check the vendor advisory for mitigations.

References

• https://github.com/copier-org/copier/commit/b3a7b3772d17cf0e7a4481978188c9f536c8d8f6
• https://github.com/copier-org/copier/security/advisories/GHSA-xjhm-gp88-8pfx

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