CVE-2026-69183Network attack vector

Mail bombing and brute-force bypass via spoofed headers

Published Aug 20, 2026 · Updated Aug 20, 2026

Rate-limit bypass in Monkeytype 26.26.0 and earlier allows remote attackers to send repeated account emails via spoofed IP headers. In backend/src/middlewares/rate-limit.ts, getKey() trusts cf-connecting-ip and x-forwarded-for before the trust-proxy-derived req.ip value, so attacker-supplied header changes create fresh limiter buckets for rootRateLimiter, badAuthRateLimiter, and the getKeyWithUid() fallback. No authentication or user interaction is required; direct-to-origin or misconfigured proxy paths can enable mail bombing, quota exhaustion, and removal of brute-force throttling on public endpoints.

CVSS severity7.5
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Rate-limit bypass in Monkeytype 26.26.0 and earlier allows remote attackers to send repeated account emails via spoofed IP headers. In backend/src/middlewares/rate-limit.ts, getKey() trusts cf-connecting-ip and x-forwarded-for before the trust-proxy-derived req.ip value, so attacker-supplied header changes create fresh limiter buckets for rootRateLimiter, badAuthRateLimiter, and the getKeyWithUid() fallback. No authentication or user interaction is required; direct-to-origin or misconfigured proxy paths can enable mail bombing, quota exhaustion, and removal of brute-force throttling on public endpoints.

The record

CVE
CVE-2026-69183
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
Monkeytype
Product
Monkeytype
Classifications
CWE-307, CWE-644, CWE-290, T1499, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 26.26.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Monkeytype · Monkeytypeversion=<= 26.26.0

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
CWE-644Improper Neutralization of HTTP Headers for Scripting Syntax
CWE-290Authentication Bypass by Spoofing
T1499Endpoint Denial of Service
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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