CVE-2026-23986: medium-severity vulnerability in copier-org copier
Copier safe template has arbitrary filesystem write access via directory symlinks when _preserve_symlinks: true
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.9epss 0.3%
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:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
copier-org · copierRelated CVEs — copier-org copier
In the same product, most dangerous first.
CVE-2026-62999HIGHCopier: Percent-encoded dot segments in template URLs can allow trusted-prefix escape (Incomplete fix for trust-prefix bypass)EPSS 0.4%CVE-2026-34726MEDIUMCopier `_subdirectory` allows template root escape via parent-directory traversalEPSS 0.4%CVE-2026-34730MEDIUMCopier `_external_data` allows path traversal and absolute-path local file read without unsafe modeEPSS 0.3%CVE-2025-55214MEDIUMCopier safe template has filesystem write access outside destination pathEPSS 0.3%CVE-2026-53951HIGHCopier: trust-prefix bypass via path traversal runs tasks unpromptedEPSS 0.3%CVE-2025-55201HIGHCopier safe template has arbitrary filesystem read/write accessEPSS 0.3%