csp-bypass-advanced

csp-bypass-advanced is a skill for Claude Code, Codex from miru-zero/zero-brain. It costs 52 tokens per session (3,248 once invoked), scanned A, a copy of csp-bypass-advanced, MIT.

A security testing guide for weaknesses in Content Security Policy (CSP), the browser rules that restrict scripts, styles, images, connections, and other page resources.

In plain words
What is it for?
Use it when reviewing XSS defenses, trusted content sources, nonce and hash handling, data-exfiltration paths, or policies involving frames and HTML injection.
Why use it?
It helps explain why a CSP may still allow attacks through trusted domains, leaked nonces, missing directives, or other policy gaps.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Not installable on its own: it reads a path above its own folder, which only exists inside its repository. The line is ├── Dangling markup injection → exfil without JS (see ../dangling-markup-injection/SKILL.md).

Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

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 csp-bypass-advanced

README.md
[![agentmods](https://agentmods.dev/badge/skills/miru-zero/zero-brain/csp-bypass-advanced.svg)](https://agentmods.dev/skills/miru-zero/zero-brain/csp-bypass-advanced)
Your own site
<a href="https://agentmods.dev/skills/miru-zero/zero-brain/csp-bypass-advanced"><img src="https://agentmods.dev/badge/skills/miru-zero/zero-brain/csp-bypass-advanced.svg" alt="Measured on agentmods" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,248 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 97% copy Near-identical to another mod 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 $0.00052 $0.03248
Opus 5 $0.00026 $0.01624
Sonnet 5 $0.00010 $0.00650
Haiku 4.5 $0.00005 $0.00325

Measured 5d ago against content hash 2b832330a8ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

csp-bypass-advanced scanned grade A with 0 findings 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 5d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

97% identical to csp-bypass-advanced — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/csp-bypass-advanced/SKILL.md · 258 lines

How it starts

The opening of the file, as written. The whole thing — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SKILL: CSP Bypass — Advanced Techniques

AI LOAD INSTRUCTION: Covers per-directive bypass techniques, nonce/hash abuse, trusted CDN exploitation, data exfiltration despite CSP, and framework-specific bypasses. Base models often suggest unsafe-inline bypass without checking if the CSP actually uses it, or miss the critical base-uri and object-src gaps.


1. CSP DIRECTIVE REFERENCE MATRIX

Directive Controls Default Fallback
default-src Fallback for all -src directives not explicitly set None (browser default: allow all)
script-src JavaScript execution default-src
style-src CSS loading default-src
img-src Image loading default-src
connect-src XHR, fetch, WebSocket, EventSource default-src
frame-src iframe/frame sources default-src
font-src Font loading default-src
object-src <object>, <embed>, <applet> default-src
media-src <audio>, <video> default-src
base-uri <base> element No fallback — unrestricted if absent
form-action Form submission targets No fallback — unrestricted if absent
frame-ancestors Who can embed this page (replaces X-Frame-Options) No fallback — unrestricted if absent
report-uri / report-to Where violation reports are sent N/A
navigate-to Navigation targets (limited browser support) No fallback

Read the full file on GitHub · 258 lines

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. 5d ago First seen · 258 lines · 52 tokens per session scan A 2b832330a8ee

Subscribe to this mod's changes

csp-bypass-advanced is a skill published in the GitHub repository miru-zero/zero-brain (0 stars, last pushed 18d ago), licensed MIT. It adds 52 tokens to every session and 3,248 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 97% identical to csp-bypass-advanced, differing in 6 lines, and is treated as a copy.

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