Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-c878-p3jh-
- https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-c878-p3jh-
FAQ
What is CVE-2026-69183?
CVE-2026-69183 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...
How severe is CVE-2026-69183?
CVE-2026-69183 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-69183?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.