External risk intelligence

Picklescan Protection Mechanism Failure Allows Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2025-10157

Picklescan is a developer-focused security tool used for scanning files, typically executed in local development environments or CI/CD pipelines. It is not an internet-facing service, gateway, or network appliance, and has no inherent public network exposure in common deployment patterns.

Mmaitre314 Picklescan

before 0.0.31

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the picklescan security scanning tool could allow attackers to bypass safety checks and execute malicious code by loading specially crafted payloads through submodules. This could lead to the execution of unauthorized code on systems where the scanner is used.

Unsafe code execution via scanner bypass.
Impacts systems using this specific security tool.
Confirm relevance and exposure of this tool.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this by sending a specially crafted file to a system running the vulnerable scanner. If the scanner incorrectly trusts this file because it's loaded as a submodule of a supposedly safe package, it can be tricked into executing malicious code. This bypasses the scanner's security checks and allows arbitrary code execution.

No authentication or privileges needed.
Loading a malicious submodule triggers vulnerability.
Leads to arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow a remote attacker to bypass security checks in the picklescan tool, leading to the execution of malicious code. This occurs when the scanner incorrectly identifies a file as safe due to an exact match for module names, enabling the loading of malicious payloads through submodules of packages. The execution of such payloads would happen when the file is loaded after a scan.

Arbitrary code execution.
Malicious payloads loaded via submodules.
Execution of unsafe code.

Operational Fix

Recommended remediation, mitigation, and detection steps

Identifying affected systems requires understanding where the `picklescan` tool is utilized, likely within development or CI/CD environments. Application owners or platform teams should be the first point of contact to confirm usage, assess business criticality, and plan remediation based on the risk of malicious code execution through submodule manipulation.

Application or platform teams own the issue.
Verify `picklescan` usage and reachability.
Plan remediation or implement controls.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the mmaitre314 picklescan tool used for?

Picklescan is a security utility designed to inspect Python pickle files for potentially malicious code before they are loaded. Developers and security engineers typically integrate it into local coding environments or automated CI/CD pipelines to ensure that serialized data files do not contain harmful instructions, protecting the system from arbitrary code execution when deserializing untrusted data.

How does CVE-2025-10157 allow a bypass of security checks?

This vulnerability is classified as a Protection Mechanism Failure (CWE-693). The scanner uses an overly restrictive check that only validates top-level module names. An attacker can circumvent this by embedding malicious code within submodules of a package. Because the scanner only compares the main package name against its list of safe modules, it mistakenly approves the entire structure, allowing the hidden malicious payload to pass undetected.

What triggers the code execution vulnerability?

The vulnerability is triggered when a user or automated process scans a maliciously crafted pickle file and subsequently loads that file into an application. The flaw does not execute code during the scanning process itself; rather, the scanner provides a false sense of security by clearing the file, which then executes its embedded malicious submodule logic only after the file is loaded into the Python environment.

Is my system at risk if I use picklescan?

According to Halo Surface Signal, it is very unlikely that your picklescan usage is internet-facing, as this tool is typically restricted to private development or CI/CD pipelines. You should care about this vulnerability if your organization processes untrusted pickle files from external sources through these internal pipelines, as that creates a pathway for malicious content to reach your build or development infrastructure.

How should I respond if I am running picklescan?

Begin by auditing your development and CI/CD environments to identify where picklescan is implemented. Once you locate these instances, prioritize updating the library to version 0.0.31 or later to resolve the submodule check flaw. In the interim, ensure that any pickle files being scanned are sourced only from trusted, internal locations rather than external or unverified repositories.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.