How severe is GHSA-955r-x9j8-7rhh?

No CVSS score has been assigned to GHSA-955r-x9j8-7rhh yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-955r-x9j8-7rhh?

GHSA-955r-x9j8-7rhh affects the following packages: picklescan (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-955r-x9j8-7rhh?

Update picklescan to 0.0.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-955r-x9j8-7rhh is resolved across your whole dependency graph.

How do I detect GHSA-955r-x9j8-7rhh in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for picklescan, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-955r-x9j8-7rhh if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is GHSA-955r-x9j8-7rhh actively exploited in the wild?

No public exploit code has been indexed for GHSA-955r-x9j8-7rhh 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.

What is the EPSS score for GHSA-955r-x9j8-7rhh?

GHSA-955r-x9j8-7rhh has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 40th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-955r-x9j8-7rhh?

GHSA-955r-x9j8-7rhh is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-955r-x9j8-7rhh published, and has it been updated?

GHSA-955r-x9j8-7rhh was published on December 30, 2025 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

Picklescan is vulnerable to RCE via missing detection when calling built-in python _operator.methodcallerGHSA-955r-x9j8-7rhh

Fix: mmaitre314/picklescan@f2dea43

GHSA-955r-x9j8-7rhh is a Deserialization of Untrusted Data vulnerability in picklescan. A fix is available for picklescan — see the affected versions and patch details below.

Also known asCVE-2025-71375

Published

Dec 30, 2025

Updated

Jul 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for GHSA-955r-x9j8-7rhh.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

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

Picklescan uses _operator.methodcaller, which is a built-in python library function to execute remote pickle files.

Details

The attack payload executes in the following steps:

First, the attacker crafts the payload by calling to _operator.methodcaller function in reduce method
Then when after the victim after checks whether or not the pickle file is safe by using Picklescan library and the library doesn't dectect any dangerous functions, pickle.load() loads this malicious pickle file, thus lead to remote code execution.

PoC

import pickle
import pickletools
opcode2 = b'''cbuiltins
__import__
(Vos
tRp0
0c_operator
methodcaller
(Vsystem
Vecho "pwned by _operator.methodcaller"
tR(g0
tR.'''
pickletools.dis(opcode2)
pickle.loads(opcode2)

This PoC can't be easily create by pickle.dumps, so it was manually built.

Impact

Any organization or individual relying on picklescan to detect malicious pickle files inside PyTorch models. Attackers can embed malicious code in pickle file that remains undetected but executes when the pickle file is loaded. Attackers can distribute infected pickle files across ML models, APIs, or saved Python objects.

Report by

Pinji Chen ([email protected]) from NISL lab (https://netsec.ccert.edu.cn/about) at Tsinghua University, Guanheng Liu ([email protected]).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`picklescan`	all versions	0.0.34`pip install --upgrade 'picklescan==0.0.34'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for picklescan, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update picklescan to 0.0.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-955r-x9j8-7rhh is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

### Summary Picklescan uses _operator.methodcaller, which is a built-in python library function to execute remote pickle files. ### Details The attack payload executes in the following steps: - First, the attacker crafts the payload by calling to _operator.methodcaller function in reduce method - Then when after the victim after checks whether or not the pickle file is safe by using Picklescan library and the library doesn't dectect any dangerous functions, pickle.load() loads this malicious pickle file, thus lead to remote code execution. ### PoC ``` import pickle import pickletools opco

O3 Security · Impact-Aware SCA

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