How severe is GHSA-r8g5-cgf2-4m4m?

No CVSS score has been assigned to GHSA-r8g5-cgf2-4m4m yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-r8g5-cgf2-4m4m?

GHSA-r8g5-cgf2-4m4m affects the following packages: picklescan (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-r8g5-cgf2-4m4m?

Update picklescan to 0.0.33 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r8g5-cgf2-4m4m is resolved across your whole dependency graph.

How do I detect GHSA-r8g5-cgf2-4m4m in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for picklescan. 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.

How do I mitigate GHSA-r8g5-cgf2-4m4m if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-r8g5-cgf2-4m4m?

O3 pinpoints whether GHSA-r8g5-cgf2-4m4m is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-r8g5-cgf2-4m4m actively exploited in the wild?

No public exploit code has been indexed for GHSA-r8g5-cgf2-4m4m yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-r8g5-cgf2-4m4m published, and has it been updated?

GHSA-r8g5-cgf2-4m4m was published on December 29, 2025 and was last updated on December 29, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

GHSA-r8g5-cgf2-4m4m

Picklescan missing detection when calling numpy.f2py.crackfortran.getlincoef

Published

Dec 29, 2025

Updated

Dec 29, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐍picklescan

Real-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

Summary

An unsafe deserialization vulnerability allows an attacker to execute arbitrary code on the host when loading a malicious pickle payload from an untrusted source.

Details

The numpy.f2py.crackfortran module exposes many functions that call eval on arbitrary strings of values. This is the case for getlincoef and _eval_length. This list is probably not exhaustive.

According to https://numpy.org/doc/stable/reference/security.html#advice-for-using-numpy-on-untrusted-data, the whole numpy.f2py should be considered unsafe when loading a pickle.

PoC

from numpy.f2py.crackfortran import getlincoef

class EvilClass:
    def __reduce__(self):
        payload = "__import__('os').system('echo \"successful attack\"')"
        return getlincoef, (payload, [])

Impact

Who is impacted? Any organization or individual relying on picklescan to detect malicious pickle files from untrusted sources. What is the impact? Attackers can embed malicious code in pickle file that remains undetected but executes when the pickle file is loaded. Supply Chain Attack: Attackers can distribute infected pickle files across ML models, APIs, or saved Python objects.

Note

The problem was originally reported to the joblib project, but this was deemed unrelated to joblib itself. However, I checked that picklescan was indeed vulnerable.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`picklescan`	all versions	0.0.33

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for picklescan. 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 picklescan to 0.0.33 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r8g5-cgf2-4m4m 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 GHSA-r8g5-cgf2-4m4m 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 GHSA-r8g5-cgf2-4m4m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary An unsafe deserialization vulnerability allows an attacker to execute arbitrary code on the host when loading a malicious pickle payload from an untrusted source. ### Details The `numpy.f2py.crackfortran` module exposes many functions that call `eval` on arbitrary strings of values. This is the case for `getlincoef` and `_eval_length`. This list is probably not exhaustive. According to https://numpy.org/doc/stable/reference/security.html#advice-for-using-numpy-on-untrusted-data, the whole `numpy.f2py` should be considered unsafe when loading a pickle. ### PoC ```python from n

O3 Security · Impact-Aware SCA

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