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K8s L4 K8S 1478 · 10 min

An Istio AuthorizationPolicy allows JWT traffic and still blocks browser clients because CORS preflight hits a rule branch with no principal

Authenticated requests pass, but preflight requests are denied before the real request can carry its token.

K8sPlatform ReliabilityLevel 4Pro10 min
Scenario

Browsers fail against a service while direct token-bearing requests from curl still succeed.

What to check first
  • Identify the primary failure signal in the The Authenticated Request Was Welcome and the Preflight Knocked on the Door Without a Principal scenario.
  • Separate visible symptoms from the underlying technical dependency.
  • Describe the safest recovery path and the follow-up prevention work.
Checking checklist
  1. Summarize the current impact and the last known change.
  2. Collect direct evidence from logs, runtime state, and configuration before changing anything.
  3. Separate immediate recovery from permanent prevention work.
Recovery and prevention

Compare preflight and authenticated branches before loosening AuthorizationPolicy for all methods.

Questions worth viewing together
Should I translate commands, logs, or product names?

No. Keep commands, logs, file names, APIs, and product names unchanged, then explain the reasoning in the selected UI language.

What should the answer focus on?

State the root cause, the evidence that supports it, and the safest recovery direction.

Why can the scenario remain in the original language?

The source scenario is treated as an incident artifact. Guidance, checklist, hints, and explanations can be localized around it.