Auditing Cors Policy

Q: What is a Claude Code skill and how does the Auditing Cors Policy skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Auditing Cors Policy is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Security · Sub-category: web-security · Last updated: 2026-06-01

type:audit type:integration

Audit a target's CORS posture — Access-Control-Allow-Origin handling, reflected-origin bypass, credentials+wildcard mismatch, preflight OPTIONS behavior, Vary header correctness. Use when: a third-party integration is failing CORS preflight and someone proposes "just set Allow-Origin to *" as the fix, OR your bug-bounty inbox has a credential-reuse exploit chain. Threshold: any reflection of arbitrary Origin into Allow-Origin, Allow-Credentials:true with wildcard origin (browser-rejected combo but server config wrong), missing Vary:Origin on per-origin responses, preflight cached over 86400s, OR Allow-Origin trust of attacker- controlled subdomain pattern. Trigger with: "audit cors", "check cors policy", "cors bypass", "preflight check".

About this skill (catalog notes)

Auditing Cors Policy includes a dedicated installation section; worked examples; 6 code blocks for direct copy-paste. The SKILL.md runs to about 727 words, in the catalog's typical mid-range.

Source: tonsofskills.com
License: MIT
Original author: Jeremy Longshore <[email protected]>
Indexed lastmod: 2026-06-01
Catalog position: Security · web-security
Indexed related skills: 10

How Auditing Cors Policy fits the catalog

Auditing Cors Policy sits in the Security category under the web-security sub-topic in the ClaudSkills catalog. There are 10 related skills indexed alongside it; comparing a few before installing usually reveals which fits your workflow best.

These notes are auto-generated from features detected in the SKILL.md file and from this catalog's structure — they aren't part of the source repository.

What this skill does

Auditing Cors Policy is a community-contributed Claude Code skill in the web-security sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/auditing-cors-policy/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when: a third-party integration is failing CORS preflight and someone proposes "just set Allow-Origin to *" as the fix, OR your bug-bounty inbox has a credential-reuse exploit chain. Threshold: any reflection of arbitrary Origin into Allow-Origin, Allow-Credentials:true with wildcard origin (browser-rejected combo but server config wrong), missing Vary:Origin on per-origin responses, preflight cached over 86400s, OR Allow-Origin trust of attacker- controlled subdomain pattern.

Who uses this skill

The Auditing Cors Policy Claude Code skill is built for security engineers, penetration testers, DevSecOps practitioners, and development teams hardening codebases and infrastructure. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 85,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/auditing-cors-policy
curl -L https://claudskills.com/skills/auditing-cors-policy/SKILL.md \
  -o ~/.claude/skills/auditing-cors-policy/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/auditing-cors-policy/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/auditing-cors-policy/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\auditing-cors-policy\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Auditing Cors Policy Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/auditing-cors-policy/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Auditing Cors Policy skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Auditing Cors Policy skill?

Use Auditing Cors Policy when your Claude Code task falls under the Security category — specifically in the web security area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Auditing Cors Policy" or describe the task and let Claude pick). Browse related skills at /category/security/.

What is a Claude Code skill and how does the Auditing Cors Policy skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Auditing Cors Policy is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/jeremylongshore/claude-code-plugins-plus-skills/blob/HEAD/plugins/security/penetration-tester/skills/auditing-cors-policy/SKILL.md
License: MIT
Author: Jeremy Longshore <[email protected]>
Website: https://tonsofskills.com

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

Jeremy Longshore <[email protected]>. (2026). Auditing Cors Policy [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/auditing-cors-policy/

BibTeX

@misc{auditing-cors-policy-2026,
  author    = {Jeremy Longshore <[email protected]>},
  title     = {Auditing Cors Policy [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/auditing-cors-policy/}
}

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