auditing-cors-and-cross-origin-trust SKILL.md skillA
auditing-cors-and-cross-origin-trust from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/auditing-cors-and-cross-origin-trust@git:20260821.57dfaf1Pins git:20260821.57dfaf1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/auditing-cors-and-cross-origin-trust/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260821.57dfaf1, committed Aug 21, 2026
- Size
- 9,590 bytes
- Repository stars
- 26
- License
- MIT
Audit the code and configuration that decide cross-origin access, for trust a browser turns into a read of authenticated data. Covers a response that reflects an arbitrary request origin into the allow-origin header alongside allow-credentials, an allowlist that accepts the null origin, allowlist matching by prefix, suffix, substring, or an unanchored pattern that a lookalike origin satisfies, the origin header trusted as an authorization or request-forgery defense, and a cross-window message…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Auditing CORS and cross-origin trust: when an attacker's origin is trusted The request origin is fully attacker-controlled: any site the victim visits sets it. Cross-origin sharing is safe only because the server decides, per origin, whether to hand back an authenticated response, and a browser enforces that decision. The bugs are all the same shape: the server trusts the origin it was told. It reflects whatever origin arrived and pairs it with credentials, so any site reads the victim's authenticated data; it matches an allowlist by substring, so a lookalike passes; it treats the origin as proof of who is calling. The client-side mirror is a message handler that acts on a posted message without checking where it came from. You find these by reading the code that builds the allow-origin decision, or handles a cross-window message, and asking whether an attacker-set origin is trusted. ## When to use - The code sets cross-origin response headers, statically or by computing them from the request origin. - An access, authorization, or request-forgery decision is made by looking at the origin or referer. - Client code receives cross-window messages and acts on their data. …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/auditing-cors-and-cross-origin-trust@sha256:b6f65d68497e0b4eThe line at the top of this page pins the label git:20260821.57dfaf1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_l6vro5sx57exdnn7)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 21, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9590 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_l6vro5sx57exdnn7 GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/auditing-cors-and-cross-origin-trust GET https://markdownregistry.com/api/v1/blob/b6f65d68497e0b4ea48addf2fa430c725cd2bbd8edc1a7430ee9fb32b37fe93c
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.