🔒 Fix race condition in SlidingWindow rate limiter

[Sanan507]

🎯 What: Fixed a race condition vulnerability in the SlidingWindow class's tryAcquire method within RateLimitFilter.java. The timestamps.size() >= limit check and the subsequent timestamps.addLast(now) operation were not executed atomically, allowing concurrent requests to bypass the limit.

⚠️ Risk: Under high concurrency (e.g., in a coordinated attack), multiple threads could simultaneously evaluate the size check as true before any of them added their timestamp to the deque. This would allow an attacker to exceed the rate limits configured to protect computationally expensive simulation endpoints from DoS attacks.

🛡️ Solution: Added the synchronized keyword to the tryAcquire method signature. This ensures that the entire process of evicting old timestamps, checking the current count, and adding the new timestamp is performed atomically per SlidingWindow instance, enforcing the rate limit correctly even under concurrent load.

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PR created automatically by Jules for task 6945787369349799329 started by @Sanan507

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Project	Deployment	Actions	Updated (UTC)
algorithm-race-visualizer	Ready	Preview	Aug 1, 2026 8:45am