CVE-2026-34726Copier `_subdirectory` allows template root escape via parent-directory traversal
- 4.4MediumCVSS base score
- 0.40%Exploitation in 30 daysEPSS · top 66% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
Copier is a library and CLI app for rendering project templates. Prior to version 9.14.1, Copier's _subdirectory setting is documented as the subdirectory to use as the template root. However, the current implementation accepts parent-directory traversal such as .. and uses it directly when selecting the template root. As a result, a template can escape its own directory and make Copier render files from the parent directory without --UNSAFE. This issue has been patched in version 9.14.1.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/copier-org/copier/security/advisories/GHSA-85v3-4m8g-hrh6 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 3 days later
· 3 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium4.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium4.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.40% · top 66% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.4.
Affected products
- affected < 9.14.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIcopierGHSA-85v3-4m8g-hrh6 (opens in a new tab)
References
References3
- https://github.com/copier-org/copier/security/advisories/GHSA-85v3-4m8g-hrh6 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/copier-org/copier/commit/cb80a3ffc9c3787de3ed837e04ca29a0ff8ca3df (opens in a new tab)x_refsource_MISC
- https://github.com/copier-org/copier/releases/tag/v9.14.1 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-18495 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-85v3-4m8g-hrh6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-34726)Record last updated .