file-upload-bypass

file-upload-bypass is a skill for Claude Code, Codex from blacklanternsecurity/red-run. It costs 15 tokens per session (5,181 once invoked), scanned B, original, GPL-3.0.

A security testing guide for bypassing restrictions on files uploaded to a website or application.

In plain words
What is it for?
Authorized penetration testing of upload forms, file-processing services, and web applications.
Why use it?
It helps reveal whether an attacker can upload dangerous files by evading checks on file types, names, or contents.

Skill for Claude CodeCodex

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

Good fit Authorized penetration testing of upload forms, file-processing services, and web applications.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/blacklanternsecurity/red-run/file-upload-bypass
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 blacklanternsecurity/red-run --skill file-upload-bypass
Clone the repo
git clone --depth 1 https://github.com/blacklanternsecurity/red-run

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 file-upload-bypass

README.md
[![agentmods](https://agentmods.dev/badge/skills/blacklanternsecurity/red-run/file-upload-bypass.svg)](https://agentmods.dev/skills/blacklanternsecurity/red-run/file-upload-bypass)
Your own site
<a href="https://agentmods.dev/skills/blacklanternsecurity/red-run/file-upload-bypass"><img src="https://agentmods.dev/badge/skills/blacklanternsecurity/red-run/file-upload-bypass.svg" alt="Measured on agentmods" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,181 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00015 $0.05181
Opus 5 $0.00008 $0.02590
Sonnet 5 $0.00003 $0.01036
Haiku 4.5 $0.00002 $0.00518

Measured 4d ago against content hash 03106c8e5e63, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade B, and why

file-upload-bypass scanned grade B 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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

test = @(http://169.254.169.254/latest/meta-data/)

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

skills/web/file-upload-bypass/SKILL.md · 625 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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 · 625 lines · 15 tokens per session scan B 03106c8e5e63

Subscribe to this mod's changes

file-upload-bypass is a skill published in the GitHub repository blacklanternsecurity/red-run (267 stars, last pushed 5mo ago), licensed GPL-3.0. It adds 15 tokens to every session and 5,181 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 1 finding (cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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