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CVE-2026-23986— Copier safe template has arbitrary filesystem write access via directory symlinks when _preserve_symlinks: true

Quick assessment

Affected
copier-org copier
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Copier是Copier开源的一个用于渲染项目模板的库。 Copier 9.11.2之前版本存在安全漏洞，该漏洞源于使用符号链接和特定设置可能导致写入目标路径之外的任意目录。

AI Predicted 7.8 Difficulty: Easy EPSS 0.27% · P18

Possible ATT&CK Techniques 1 AI

T1053 · Scheduled Task/Job
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I. Basic Information for CVE-2026-23986

Vulnerability Information
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Vulnerability Title
Copier safe template has arbitrary filesystem write access via directory symlinks when _preserve_symlinks: true
Source: CVE Program / CVE List V5
Vulnerability 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 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
CWE-61
Source: CVE Program / CVE List V5
Vulnerability Title
Copier 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Copier是Copier开源的一个用于渲染项目模板的库。 Copier 9.11.2之前版本存在安全漏洞，该漏洞源于使用符号链接和特定设置可能导致写入目标路径之外的任意目录。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
copier-org copier < 9.11.2 -

II. Public POCs for CVE-2026-23986

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III. Intelligence Information for CVE-2026-23986

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Vendor Advisories for CVE-2026-23986 (1)

IV. Related Vulnerabilities

Same product: copier
Same vendor: copier-org
Same weakness: CWE-61