CVE-2026-69183 (GCVE-0-2026-69183)

Vulnerability from cvelistv5 – Published: 2026-08-20 16:16 – Updated: 2026-08-20 17:14
VLAI
Title
Monkeytype: Rate-limit and anti-brute-force controls bypassable via spoofed HTTP headers (forgotPasswordEmail/verificationEmail mail bombing and badAuth bypass)
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-20 17:13 UTC
CWE
  • CWE-290 - Authentication Bypass by Spoofing
  • CWE-307 - Improper Restriction of Excessive Authentication Attempts
  • CWE-644 - Improper Neutralization of HTTP Headers for Scripting Syntax
Assigner
References
Impacted products
Vendor Product Version
monkeytypegame monkeytype Affected: <= 26.26.0
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