Secure, HttpOnly, and SameSite cookies protect different boundaries

Secure restricts a cookie's transmission to HTTPS, subject to documented localhost behavior. HttpOnly prevents ordinary script APIs from reading that cookie. SameSite determines when it accompanies cross-site requests. None of these names implies the other properties are enabled.

Illustrative example: a session cookie can be HttpOnly yet still accompany a request initiated by JavaScript. That flag reduces direct script access to the cookie value; it does not disable all actions that a compromised page might make using the session.

For an HTTPS session, evaluate Secure and HttpOnly explicitly. Choose SameSite according to required navigation and authentication flows: Strict and Lax differ on cross-site sending; None permits cross-site use and requires Secure. Test legitimate sign-in returns and embedded use cases rather than assuming the strictest setting preserves every workflow.

Also keep cookie scope narrow. Path matching selects requests to which a cookie is sent; it is not a reliable security boundary between applications on the same host.

Limit: cookie attributes do not repair an authorization flaw, guarantee immunity to script injection, or protect a compromised endpoint. Browser behavior and third-party-cookie restrictions can add further constraints beyond these attributes.