CVE-2026-34726

Summary

Copier is a library and CLI app for rendering project templates. Prior to version 9.14.1, Copier's _subdirectory setting is documented as the subdirectory to use as the template root. However, the current implementation accepts parent-directory traversal such as .. and uses it directly when selecting the template root. As a result, a template can escape its own directory and make Copier render files from the parent directory without –UNSAFE. This issue has been patched in version 9.14.1.

Affected Software

Weaknesses

• CWE-22: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: poc
  • Automatable: no
  • Technical Impact: partial

Additional References

• https://github.com/copier-org/copier/security/advisories/GHSA-85v3-4m8g-hrh6

References

• https://github.com/copier-org/copier/security/advisories/GHSA-85v3-4m8g-hrh6
• https://github.com/copier-org/copier/commit/cb80a3ffc9c3787de3ed837e04ca29a0ff8ca3df
• https://github.com/copier-org/copier/releases/tag/v9.14.1

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