High

PDM Trojan Lockfile

  • Disclosed: 20.10.2023
  • Updated: 11.10.2026 13:18

Summary

It's possible to craft a malicious pdm.lock file that could allow e.g. an insider or a malicious open source project to appear to depend on a trusted PyPI project, but actually install another project.

Details

Project foo can be targeted by creating the project foo-2 and uploading the file foo-2-2.tar.gz to pypi.org. PyPI will see this as project foo-2 version 2, while PDM will see this as project foo version 2-2. The version must only be parseable as a version (and the filename must be a prefix of the project name), but it's not verified to match the version being installed. (Version 2-2 is also not a valid normalized version per PEP 440.)

Matching the project name exactly (not just prefix) would fix the issue. The version should also be verified to avoid version downgrade attacks.

PoC

Example pdm.lock snippet to appear to depend on foo but actually install foo-2

"foo 2.2.0" = [
  url = "https://files.pythonhosted.org/.../foo-2-2.tar.gz
]

Impact

When installing dependencies with PDM, what's actually installed could differ from what's listed in pyproject.toml (including arbitrary code execution on install). It could also be used for downgrade attacks by only changing the version.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) pdm <= 2.9.3 no fix

References

CVSS score 7.8/10
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-20
Platform
Python (PyPI)
Package
pdm
Disclosed
20.10.2023
Updated
11.10.2026 13:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-1763 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-j44v-mmf2-xvm9 - CC BY 4.0

Vulnerability history: pdm

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
4
First → latest
10.2023 06.2026
Without a fix
1
Exploited in attacks
0

Severity breakdown

  • High 3
  • Medium 1

Disclosures per year

  1. 2023: 1
  2. 2024: 0
  3. 2025: 0
  4. 2026: 3
  1. Medium CVE-2026-47763 < 2.27.0 2.27.0
  2. PDM Trojan Lockfile this entry
    High · 7.8 CVE-2023-45805 <= 2.9.3 no fix

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