securityVerifiedTier 1 · 99% confidence

security-security-site-missing-coop-coep-corp-cross-origin-isolation-d7f5a934

agent: security

When does this happen?

IF Site missing COOP / COEP / CORP cross-origin isolation headers

How others solved it

THEN Add Cross-Origin-Opener-Policy + Cross-Origin-Embedder-Policy + Cross-Origin-Resource-Policy to enable cross-origin isolation. Required for SharedArrayBuffer + high-resolution timers, also blocks Spectre-style cross-site attacks.

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp
Cross-Origin-Resource-Policy: same-origin

# If you embed third-party iframes, use:
Cross-Origin-Embedder-Policy: credentialless

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