Cross-Origin Embedder Policy (COEP)
¿Qué es Cross-Origin Embedder Policy (COEP)?
Cross-Origin Embedder Policy (COEP)An HTTP response header that forces every cross-origin subresource a document loads to explicitly opt in via CORS or CORP, completing the cross-origin isolation prerequisites alongside COOP.
Cross-Origin Embedder Policy (`Cross-Origin-Embedder-Policy`) is a browser security header that controls whether a document is allowed to embed cross-origin subresources without an explicit opt-in. With `require-corp`, every image, script, iframe, font, or other cross-origin asset must carry either a CORS response (`Access-Control-Allow-Origin`) or a Cross-Origin-Resource-Policy (CORP) header that authorizes the embed; otherwise the load fails. With `credentialless`, cross-origin requests for no-CORS resources are sent without cookies and treated as anonymous. COEP exists primarily to enable cross-origin isolation: when paired with `Cross-Origin-Opener-Policy: same-origin`, it unlocks high-resolution timers, `SharedArrayBuffer`, and other features that were restricted to mitigate Spectre. Deploying COEP often requires auditing third-party assets to ensure they ship `Cross-Origin-Resource-Policy: cross-origin` or proper CORS.
● Ejemplos
- 01
A WebAssembly-heavy app sends `Cross-Origin-Embedder-Policy: require-corp` and `Cross-Origin-Opener-Policy: same-origin` to re-enable `SharedArrayBuffer`.
- 02
A CDN that serves third-party scripts adds `Cross-Origin-Resource-Policy: cross-origin` so its assets remain embeddable in COEP-enforcing pages.
● Preguntas frecuentes
¿Qué es Cross-Origin Embedder Policy (COEP)?
An HTTP response header that forces every cross-origin subresource a document loads to explicitly opt in via CORS or CORP, completing the cross-origin isolation prerequisites alongside COOP. Pertenece a la categoría de Seguridad de aplicaciones en ciberseguridad.
¿Qué significa Cross-Origin Embedder Policy (COEP)?
An HTTP response header that forces every cross-origin subresource a document loads to explicitly opt in via CORS or CORP, completing the cross-origin isolation prerequisites alongside COOP.
¿Cómo funciona Cross-Origin Embedder Policy (COEP)?
Cross-Origin Embedder Policy (`Cross-Origin-Embedder-Policy`) is a browser security header that controls whether a document is allowed to embed cross-origin subresources without an explicit opt-in. With `require-corp`, every image, script, iframe, font, or other cross-origin asset must carry either a CORS response (`Access-Control-Allow-Origin`) or a Cross-Origin-Resource-Policy (CORP) header that authorizes the embed; otherwise the load fails. With `credentialless`, cross-origin requests for no-CORS resources are sent without cookies and treated as anonymous. COEP exists primarily to enable cross-origin isolation: when paired with `Cross-Origin-Opener-Policy: same-origin`, it unlocks high-resolution timers, `SharedArrayBuffer`, and other features that were restricted to mitigate Spectre. Deploying COEP often requires auditing third-party assets to ensure they ship `Cross-Origin-Resource-Policy: cross-origin` or proper CORS.
¿Cómo defenderse de Cross-Origin Embedder Policy (COEP)?
Las defensas contra Cross-Origin Embedder Policy (COEP) combinan habitualmente controles técnicos y prácticas operativas, como se detalla en la definición.
¿Cuáles son otros nombres para Cross-Origin Embedder Policy (COEP)?
Nombres alternativos comunes: COEP.
● Términos relacionados
- appsec№ 263
Cross-Origin Opener Policy (COOP)
An HTTP response header that lets a document opt into a process-isolated browsing context group, preventing cross-origin windows from inspecting or manipulating it via `window.opener` and friends.
- appsec№ 246
CORS (Intercambio de Recursos entre Orígenes)
Mecanismo aplicado por el navegador que permite a un servidor relajar selectivamente la política del mismo origen para que JavaScript de un origen pueda leer respuestas de otro.
- appsec№ 237
Política de Seguridad de Contenidos (CSP)
Cabecera HTTP que indica al navegador qué orígenes de scripts, estilos, marcos y otros recursos están permitidos, limitando el impacto de XSS y de inyecciones de datos.
- appsec№ 552
Cabeceras de seguridad HTTP
Cabeceras de respuesta que instruyen a los navegadores a aplicar comportamientos defensivos como HTTPS obligatorio, restricciones de marco, políticas de contenido y control de referer.
- appsec№ 1164
Aislamiento de Sitios
Arquitectura de seguridad de Chromium que coloca documentos de sitios distintos en procesos separados del sistema operativo para que un renderer comprometido no acceda a datos de otros sitios.
- vulnerabilities№ 1192
Spectre
Familia de ataques microarquitectónicos que abusan de la ejecución especulativa de la CPU para filtrar datos a través de canales laterales de caché entre fronteras de seguridad.
● Véase también
- № 911Permissions-Policy