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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 262

Cross-Origin Embedder Policy (COEP)

Cross-Origin Embedder Policy (COEP) 是什么?

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.

示例

  1. 01

    A WebAssembly-heavy app sends `Cross-Origin-Embedder-Policy: require-corp` and `Cross-Origin-Opener-Policy: same-origin` to re-enable `SharedArrayBuffer`.

  2. 02

    A CDN that serves third-party scripts adds `Cross-Origin-Resource-Policy: cross-origin` so its assets remain embeddable in COEP-enforcing pages.

常见问题

Cross-Origin Embedder Policy (COEP) 是什么?

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. 它属于网络安全的 应用安全 分类。

Cross-Origin Embedder Policy (COEP) 是什么意思?

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 (COEP) 是如何工作的?

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.

如何防御 Cross-Origin Embedder Policy (COEP)?

针对 Cross-Origin Embedder Policy (COEP) 的防御通常结合技术控制与运营实践,详见上方完整定义。

Cross-Origin Embedder Policy (COEP) 还有哪些其他名称?

常见的别称包括: COEP。

相关术语

参见