CVE-2026-34730 json
Copier `_external_data` allows path traversal and absolute-path local file read without unsafe mode
published 2026-04-01 7 mo ago modified 2026-07-24 3 mo ago also GHSA-hgjq-p8cr-gg4h , PYSEC-2026-2135 , EUVD-2026-18497
- cvss
- 5.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 22%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi copier 9.14.1
- copier-org copier 9.14.1
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
| OSV | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | copier | <9.14.1 |
9.14.1 |
Affected products
- copier-org copier
Classification
- Weakness
-
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory
References
-
github.com
/copier-org/copier/commit/5413062eb17b73dc885f5e645cdc161e69ef641b
web, patch
-
github.com
/copier-org/copier/security/advisories/GHSA-hgjq-p8cr-gg4h
exploit, web, vendor-advisory, evidence
-
github.com
/copier-org/copier/releases/tag/v9.14.1
web, release-notes, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-34730
advisory
-
github.com
/copier-org/copier
package
Sources
- CVE List CVE-2026-34730
- GitHub Advisory GHSA-hgjq-p8cr-gg4h
- NVD CVE-2026-34730
- OSV PYSEC-2026-2135
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.