CVE-2026-33640

CRITICAL

9.8

Description

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.

CVE Details

CVSS v3.1 Score9.8

SeverityCRITICAL

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/26/2026

Last Modified3/31/2026

Sourcenvd

Honeypot Sightings0

Affected Products

getoutline:outline

Weaknesses (CWE)

CWE-307

References

https://github.com/outline/outline/releases/tag/v1.6.0(security-advisories@github.com)

https://github.com/outline/outline/security/advisories/GHSA-cwhc-53hw-qqx6(security-advisories@github.com)

IOC Correlations

No correlations recorded

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