CRITICALCWE-436
PARSE-005 JSON Duplicate Key Override
Parser Differential: Exploits differences in how parsers (JSON, YAML, markdown) interpret the same input to bypass security controls
Description
Exploits parsers that handle duplicate JSON keys differently: first-wins vs last-wins semantics to smuggle hidden values
Remediation
Reject JSON with duplicate keys. Use strict parsing that errors on duplicates rather than silently accepting first or last value.