Defaults.Exposed › September 2026 census › v10 registry › CORP (Cross-Origin-Resource-Policy)
CORP (Cross-Origin-Resource-Policy)
Methodology v10 · canonical ID corp-header · Web Security · informational · census as of September 5, 2026
Advanced isolation that hardens against cross-site data leaks.
Definition
| Canonical ID | corp-header |
|---|---|
| Category | Web Security |
| Grade impact | Informational, never moves the grade |
| Pass | The site sends a Cross-Origin-Resource-Policy header. |
| Fail | The header is absent. |
| Example (passing) | Cross-Origin-Resource-Policy: same-origin |
No-data rule: when this check couldn't be determined for a domain (timeout, SERVFAIL, redacted source) it returns N/A and is excluded from that domain's scoring denominator: "couldn't determine" is never counted as a failure. "Determined absent" is a real fail.
Prevalence across the census
The public census rollup does not publish a per-check figure for corp-header (as of September 5, 2026).
Whole-census aggregates live at /data; no number is shown here rather than an estimated one.
Census denominator: 316,600,902 graded domains. Aggregates only: never an individual domain's result.
Fix it
Plain-English impact, cost of ignoring it, and step-by-step remediation: defaults.exposed/fix/cross-origin-headers
Cite this check
Defaults.Exposed, "CORP (Cross-Origin-Resource-Policy) (corp-header)", Grading Methodology v10 (census as of September 5, 2026). https://defaults.exposed/methodology/corp-header
Permalink: https://defaults.exposed/methodology/corp-header ·
All 34 checks: v10 registry ·
Machine-readable: /methodology/checks.json ·
Licence: open data