CVE-2026-34730: Copier is a library and CLI app for rendering project templates

Routine

MEDIUM 5.5UPGRADE

CVE-2026-34730 is a medium-severity flaw (CVSS 5.5) affecting copier. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-22
Published	2026-04-02
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: copier-org

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-02 19:21 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

copier-org copier UPGRADE

Affected: < 9.14.1

Fixed in: 9.14.1

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show copier

2. UPGRADE to 9.14.1

pip install --upgrade "copier>=9.14.1"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34730?

copier: upgrade to 9.14.1. Exact commands for each OS are on this page.

Is CVE-2026-34730 being exploited?

CVE-2026-34730 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34730 affect?

CVE-2026-34730 affects copier. Severity is medium (CVSS 5.5). 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

How urgent is CVE-2026-34730?

Priority 30/100. Public exploit reference

Related CVEs

CVE-2026-34726 MEDIUM 4.4 UPGRADE Copier is a library and CLI app for rendering project templates

References

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