Session Cookie Missing 'SameSite' Attribute
Without SameSite, browsers attach this session cookie to requests made from other sites.
Why it matters
Without SameSite, browsers attach this session cookie to requests made from other sites. That is what makes cross-site request forgery possible: a page elsewhere can trigger an authenticated action on yours while the user is logged in.
How ShipReady detects it
Inspects Set-Cookie on responses the scan already fetched. Only cookies whose name suggests a session — containing session, token, auth, sid, jwt, user or login — are examined. A preference or analytics cookie missing HttpOnly is not a finding worth anyone's attention, and flagging it would bury the one that matters. Flags are parsed from the raw header rather than a cookie library, because valueless attributes are dropped by some parsers and their absence is exactly what this check exists to detect. Runs on every crawled page, which is what makes it useful: a logged-out homepage usually sets nothing at all, while /login sets the cookie whose flags actually matter.
Detection is deterministic. ShipReady reports this only when it observes the condition directly, and prefers to miss a real problem over inventing one. Rule version 1.2.0.
How to fix it
This is the prompt ShipReady puts in your report — written to be pasted straight into Cursor, Claude Code, or whichever assistant built the app.
The affected session cookie is missing a strict 'SameSite' attribute. This exposes the application to CSRF attacks. Set SameSite=Lax or SameSite=Strict.
Frequently asked questions
- What does "Session Cookie Missing 'SameSite' Attribute" mean?
- Without SameSite, browsers attach this session cookie to requests made from other sites.
- How serious is it?
- ShipReady rates this medium. Fix soon. Meaningfully weakens a defence or degrades how the site works.
- How do I fix it?
- Paste the fix prompt on this page into Cursor, Claude Code or your AI editor. It is the same prompt ShipReady puts in your report.
- Can I check my own site?
- Yes — ShipReady scans up to ten pages of any public site for free and reports this alongside every other check. The free report lists every issue it finds and shows full evidence and a fix prompt for the critical and high-severity ones; medium and low findings are counted and unlock on Pro.
Related checks
Run this check on your site
ShipReady checks this and 193 other things across up to ten pages of your site, with an AI-ready fix for each. Free, no signup.