Parent-file rendering via unchecked subdirectory traversal
Published Apr 2, 2026 · Updated Apr 2, 2026
Path traversal in Copier before 9.14.1 allows local users to render files outside a template root through a crafted template. The template_copy_root property renders _subdirectory and joins it directly to template.local_abspath without verifying that the resolved path remains beneath the template directory. Exploitation requires a user to process an attacker-controlled template; successful traversal can expose or incorporate parent-directory files without enabling unsafe mode.
Summary
What happened
Path traversal in Copier before 9.14.1 allows local users to render files outside a template root through a crafted template. The template_copy_root property renders _subdirectory and joins it directly to template.local_abspath without verifying that the resolved path remains beneath the template directory. Exploitation requires a user to process an attacker-controlled template; successful traversal can expose or incorporate parent-directory files without enabling unsafe mode.
The record
- CVE
- CVE-2026-34726
- Published
- Apr 2, 2026
- Updated
- Apr 2, 2026
- Vendor
- copier-org
- Product
- Copier
- Classifications
- CWE-22, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 2, 2026CVE publishedPublication date reported by the CVE source.
- Apr 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 9.14.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream template-root escape proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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