cross-origin-security SKILL.md skillA
cross-origin-security from thedaviddias/front-end-checklist is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add thedaviddias/front-end-checklist/cross-origin-security@git:20261004.4b0ddb9Pins git:20261004.4b0ddb9 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- thedaviddias/front-end-checklist
- Path
skills/cross-origin-security/SKILL.md- Versions recorded
- 2
- Latest version
- git:20261004.4b0ddb9, committed Oct 4, 2026
- First version recorded
- May 29, 2026
- Size
- 2,382 bytes
- Repository stars
- 74,516
- License
- MIT
Use when reviewing scripts, client components, bundles, or runtime behavior related to Handle cross-origin requests securely. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug.
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
# Handle cross-origin requests securely The Same-Origin Policy is the browser's primary defense against malicious sites stealing data or performing actions on behalf of your users. Misconfiguring CORS or failing to validate postMessage origins can allow attackers to bypass this protection — reading private data, submitting forms as users, or injecting content into your pages. ## Quick Reference - Always verify event.origin before processing postMessage data - Never set Access-Control-Allow-Origin: * for authenticated endpoints - Validate and sanitize all data received from cross-origin messages - Use SameSite cookies to prevent CSRF from cross-origin requests - Reject unvalidated redirect targets such as `next`, `redirect`, or `callbackUrl` ## Check Check this code for insecure cross-origin patterns: missing origin validation in postMessage listeners, overly permissive CORS settings, and missing CSRF protections. Flag redirect parameters that accept arbitrary external URLs. ## Fix …
Read the whole file at its exact version.
How to install
mdr add thedaviddias/front-end-checklist/cross-origin-security@sha256:0a2478527b8faf6aThe line at the top of this page pins the label git:20261004.4b0ddb9, 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_oxojd2zj57w5nzkd)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between May 29, 2026 and Oct 4, 2026, about one every 128 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261004.4b0ddb9 latest | 2026-10-04 | 4b0ddb9 | 2,382 B | A | view · diff |
| git:20260529.7c05904 | 2026-05-29 | 7c05904 | 2,388 B | A | view |
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 (2382 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
thedaviddias/front-end-checklist · 74,516 stars · license MIT · pushed 2026-10-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_oxojd2zj57w5nzkd GET https://markdownregistry.com/api/v1/resolve?ref=thedaviddias/front-end-checklist/cross-origin-security GET https://markdownregistry.com/api/v1/blob/0a2478527b8faf6afeb0efde579e25c00711d808727d62ee301492b9fc3a5aab
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.