This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Natao arisiva ity resaka mitohy ity. Mametraha fanontaniana azafady raha mila fanampiana.

Firefox claims SameSite is set to Lax, while set-cookie contains SameSite=None and Secure

Øyvind Wergeland
Øyvind Wergeland
more options

Our backend sets a cookie for maintaining login sessions with SameSite=None and Secure (to support loading our front-end from localhost for developers and from a third party domain for PR previews).

This is the respose header:

set-cookie: ESESSIONID=<redacted>; Secure; HttpOnly; Path=/; SameSite=None; Max-Age=86399

However, Firefox does not send the cookie back with requests, but logs this error in the console:

Cookie “ESESSIONID” has been rejected because it is in a cross-site context and its “SameSite” is “Lax” or “Strict”.

We have worked around the issue by configuring exceptions in the Security & Privacy settings, but I am curious to why Firefox rejects the cookie with this error message.

Our backend sets a cookie for maintaining login sessions with SameSite=None and Secure (to support loading our front-end from localhost for developers and from a third party domain for PR previews). This is the respose header: set-cookie: ESESSIONID=<redacted>; Secure; HttpOnly; Path=/; SameSite=None; Max-Age=86399 However, Firefox does not send the cookie back with requests, but logs this error in the console: Cookie “ESESSIONID” has been rejected because it is in a cross-site context and its “SameSite” is “Lax” or “Strict”. We have worked around the issue by configuring exceptions in the Security & Privacy settings, but I am curious to why Firefox rejects the cookie with this error message.

All Replies (1)

Øyvind Wergeland
Øyvind Wergeland Tompon'ny fanontaniana
more options

I am not sure what you mean by "the site in question"? In production our back-end and front-end are served from two different subdomains of our domain, and here Firefox works with default settings.

The issue occurs when developers run the front-end from localhost (served by webpack-dev-server), and logs into our back-end. The ESSESSIONID cookie is set in the response to our callback endpoint for authorization code flow in our back-end.

It takes some effort to set up a public repro, and we are able to work around it, but I am curious to why Firefox logs an error that seems to contradict the set-cookie header.