CVE-2026-47763
CVE-2026-47763 is a CWE-61 vulnerability in pdm. O3 Security confirms whether CVE-2026-47763 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
pdm: Project-Local State and Config Writes Follow Symlinks
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47763.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
pdmReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
pdm is a Python package and dependency manager supporting the latest PEP standards. In versions prior to 2.27.0, pdm writes several project-local state or configuration files without symlink protection. If a malicious repository places those files as symlinks, local PDM operations can overwrite the symlink targets. This creates an arbitrary file clobber primitive relative to the privileges of the invoking user. Config.init() resolves the project-local pdm.toml path and _save_config() writes to the resolved target. If PROJECT_ROOT/pdm.toml is a symlink to another file, pdm config -l ... updates the target file instead of refusing the write. The same general problem exists for other project-local persistence paths that are written directly with no lstat / O_NOFOLLOW protection. For the pdm.toml PoC specifically, the target file must already contain parseable TOML. Otherwise the load step fails before the write path is reached. That parser constraint does not apply to the .pdm-python or .python-version sinks. This issue has been fixed in version 2.27.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pdm | all versions | 2.27.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pdm. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pdm to 2.27.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47763 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-47763 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-47763. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-47763 in your dependencies?
O3 detects CVE-2026-47763 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.