Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

Avatar for Username

ابحث في الدعم

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

This thread was archived. Please ask a new question if you need help.

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 صاحب السؤال
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.