PYSEC-2026-1553 Litestar X-Forwarded-For Header Spoofing Vulnerability Enables Rate Limit Evasion

While testing Litestar's RateLimitMiddleware, I discovered that rate limits can be completely bypassed by manipulating the X-Forwarded-For header. This renders IP-based rate limiting ineffective against determined attackers. The Problem Litestar's RateLimitMiddleware uses cachekeyfromrequest to...