CyberRota Analysis
AI-GeneratedThe vulnerability affects the backend of Monkeytype, specifically in the rate-limit key generator, allowing unauthenticated attackers to manipulate client-controlled headers to bypass rate limiting on public endpoints. This can lead to mail bombing of registered users, resource exhaustion, and evasion of brute-force protections, significantly impacting user accounts and service availability. Organizations using Monkeytype, particularly those with public-facing services, should prioritize remediation efforts to mitigate potential abuse and service disruption.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Monkeytype is a minimalistic and customizable typing test. In 26.26.0 and earlier, the backend rate-limit key generator in backend/src/middlewares/rate-limit.ts uses client-controlled cf-connecting-ip and x-forwarded-for headers before the trust-proxy-derived req.ip value. An unauthenticated attacker can rotate either header to create a new bucket for each request, bypassing rootRateLimiter, badAuthRateLimiter, getKey(), and the getKeyWithUid() fallback used by public endpoints. This permits repeated POST /users/forgotPasswordEmail and verificationEmail requests, mail bombing registered users, consuming Firebase or SMTP quota, evading brute-force protection, and enabling resource exhaustion. Exploitability of cf-connecting-ip depends on deployment topology, but x-forwarded-for and direct-to-origin paths remain affected when those values are not overwritten by a trusted proxy. No fixed version is available as of this review.