Scenario
A cookie hardening rollout leaves some browsers or embedded login flows broken while ordinary browser login still succeeds.
A SameSite hardening change breaks SSO only on one browser flow because that path depends on a cross-site POST or embedded return that no longer sends the cookie
Simple redirects still work, yet one login surface loops because the stricter cookie policy withholds session state in a context the app relied on.
What to check first
- Identify the primary failure signal in the Cross-Site Return Lost to SameSite Policy scenario.
- Separate visible symptoms from the underlying technical dependency.
- Describe the safest recovery path and the follow-up prevention work.
Checking checklist
- Summarize the current impact and the last known change.
- Collect direct evidence from logs, runtime state, and configuration before changing anything.
- Separate immediate recovery from permanent prevention work.
Recovery and prevention
Trace the exact browser context of the failing return before changing redirect URIs or IdP config.
Questions worth viewing together
Community-field security problem inspired by Stack Overflow threads where SameSite cookie hardening broke only certain SSO return paths. SameSite issues often affect only the one return path that crosses a context boundary the team forgot to model.
Teams often blame the provider when the browser is simply withholding the cookie under the new policy.
Browser-specific SameSite behavior makes these regressions look intermittent until the exact flow is mapped.
Similar cases seen in the field