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CVE-2026-33640

Outline has a rate limit bypass that allows brute force of email login OTP

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.6.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: total

Summary

Outline is a service that allows for collaborative documentation. Outline implements an Email OTP login flow for users not associated with an Identity Provider. Starting in version 0.86.0 and prior to version 1.6.0, Outline does not invalidate OTP codes based on amount or frequency of invalid submissions, rather it relies on the rate limiter to restrict attempts. Consequently, identified bypasses in the rate limiter permit unrestricted OTP code submissions within the codes lifetime. This allows attackers to perform brute force attacks which enable account takeover. Version 1.6.0 fixes the issue.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: total

  3. Record last updated

Affected versions

  • outline outline

    From 0.86.0 · fixed in 1.6.0

References 2

GitHub · outline/outline