CVE-2026-23986

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 write to arbitrary directories outside the destination path by using directory a symlink along with `_preserve_symlinks: true` and a generated directory structure whose rendered path is inside the symlinked directory. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. Version 9.11.2 patches the issue.

CVSS v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/copier-org/copier/commit/b3a7b3772d17cf0e7a4481978188c9f536c8d8f6	Patch
https://github.com/copier-org/copier/releases/tag/v9.11.2	Product Release Notes
https://github.com/copier-org/copier/security/advisories/GHSA-4fqp-r85r-hxqh	Exploit Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:copier-org:copier:*:*:*:*:*:python:*:*

History

No history.

Information

Published : 2026-01-21 23:15

Updated : 2026-02-02 14:10

NVD link : CVE-2026-23986

Mitre link : CVE-2026-23986

CVE.ORG link : CVE-2026-23986

JSON object : View

Products Affected

copier-org

copier

CWE

CWE-61

UNIX Symbolic Link (Symlink) Following

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