CVE-2026-69183: Brute Force (CVSS 7.5)

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.

Is your site exposed to CVE-2026-69183?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-290 CWE-290

CWE-307 CWE-307

CWE-644 CWE-644

References

Other References

https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-c878-p3jh-mmjf https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-c878-p3jh-mmjf

Frequently Asked Questions

What is CVE-2026-69183? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-69183? +

CVE-2026-69183 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-69183? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6213

A vulnerability in Remote Spark SparkView before build 1122 allows an attacker to bypasses the local connection check and achieve …

CVE-2026-34025

The Wertheim SafeController Software, AssemblyVersion 6.15.8328.28014, contains an IP restriction bypass vulnerability in the login process. The application restricts user …

CVE-2025-22271

The application or its infrastructure allows for IP address spoofing by providing its own value in the "X-Forwarded-For" header. Thus, …

CVE-2025-31122

scratch-coding-hut.github.io is the website for Coding Hut. In 1.0-beta3 and earlier, the login link can be used to login to …

CVE-2025-46345

Auth0 Account Link Extension is an extension aimed to help link accounts easily. Versions 2.3.4 to 2.6.6 do not verify …

CVE-2025-34053

An authentication bypass vulnerability exists in AVTECH IP camera, DVR, and NVR devices’ streamd web server. The strstr() function is …

CVE-2026-69183