Copier `_external_data` allows path traversal and absolute-path local file read without unsafe mode

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-34730
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-02 19:21:32 UTC
Updated2026-04-02 19:21:32 UTC
DescriptionCopier is a library and CLI app for rendering project templates. Prior to version 9.14.1, Copier's _external_data feature allows a template to load YAML files using template-controlled paths. If untrusted templates are in scope, a malicious template can read attacker-chosen YAML-parseable local files that are accessible to the user running Copier and expose their contents in rendered output. This issue has been patched in version 9.14.1.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1CNADECLARED5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Copier-org Copier affected < 9.14.1 Not specified

References

ReferenceSourceLinkTags
github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h [email protected] github.com
github.com/copier-org/copier/releases/tag/v9.14.1 [email protected] github.com
github.com/copier-org/copier/commit/5413062eb17b73dc885f5e645cdc161e69ef... [email protected] github.com
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