Which response header specifically protects against speculative execution attacks, such as Spectre, in addition to mitigating XSS inclusion attacks?

The correct response header that specifically protects against speculative execution attacks, such as Spectre, as well as mitigating XSS inclusion attacks, is the Cross-Origin Resource Policy (CORP). This header plays a crucial role in controlling how resources are shared and can help mitigate certain types of security risks, particularly in web applications.

CORP is designed to restrict which origins are permitted to load a resource. By setting this policy, it essentially informs the browser about how to handle cross-origin requests, which can prevent untrusted origins from being able to execute scripts or access resources that could lead to vulnerabilities, including those exploited by speculative execution attacks. This capability helps in reducing the attack surface for such risks, thereby enhancing the overall security of applications.

In addition to protecting against cross-origin resource sharing issues, CORP also reinforces defenses against certain attacks that rely on the execution of untrusted content, like XSS, by ensuring that only appropriately configured origins are allowed to participate in resource sharing. Thus, it serves to harden the application’s defenses in multiple dimensions.

Other headers mentioned, while they serve important security purposes, do not directly provide the same level of protection against speculative execution vulnerabilities as CORP does.