python-prototype-pollution

python-prototype-pollution is a skill for Claude Code, Codex from wgpsec/AboutSecurity. It costs 116 tokens per session (1,657 once invoked), scanned A, original, no licence file.

A guide to finding and exploiting class pollution in Python web applications, where user-controlled data changes object attributes or application settings.

In plain words
What is it for?
Authorized testing of Flask, Sanic, Django, or FastAPI applications with JSON configuration or object-update endpoints.
Why use it?
It helps reveal unsafe recursive data merging and deep property updates that may expose secrets, read files, change permissions, or run code.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit Authorized testing of Flask, Sanic, Django, or FastAPI applications with JSON configuration or object-update endpoints.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/wgpsec/aboutsecurity/python-prototype-pollution
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add wgpsec/AboutSecurity --skill python-prototype-pollution
Clone the repo
git clone --depth 1 https://github.com/wgpsec/AboutSecurity

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for python-prototype-pollution

README.md
[![agentmods](https://agentmods.dev/badge/skills/wgpsec/aboutsecurity/python-prototype-pollution.svg)](https://agentmods.dev/skills/wgpsec/aboutsecurity/python-prototype-pollution)
Your own site
<a href="https://agentmods.dev/skills/wgpsec/aboutsecurity/python-prototype-pollution"><img src="https://agentmods.dev/badge/skills/wgpsec/aboutsecurity/python-prototype-pollution.svg" alt="Measured on agentmods" height="20"></a>
Per session 116 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,657 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Data Exfiltration · line 54
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
Origin unknown No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00116 $0.01657
Opus 5 $0.00058 $0.00829
Sonnet 5 $0.00023 $0.00331
Haiku 4.5 $0.00012 $0.00166

Measured 4d ago against content hash 1ffb0ba287af, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

python-prototype-pollution scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -X POST http://target/api/merge \
skills/exploit/web-method/python-prototype-pollution/SKILL.md · 113 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 113 lines · 116 tokens per session scan A 1ffb0ba287af

Subscribe to this mod's changes

python-prototype-pollution is a skill published in the GitHub repository wgpsec/AboutSecurity (1,721 stars, last pushed 8d ago), with no licence file. It adds 116 tokens to every session and 1,657 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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