Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Getoutline | Outline | >= 0.86.0, < 1.6.0 |
Related Weaknesses (CWE)
References
- https://github.com/outline/outline/releases/tag/v1.6.0Release Notes
- https://github.com/outline/outline/security/advisories/GHSA-cwhc-53hw-qqx6ExploitVendor Advisory
FAQ
What is CVE-2026-33640?
CVE-2026-33640 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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...
How severe is CVE-2026-33640?
CVE-2026-33640 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-33640?
Check the references section above for vendor advisories and patch information. Affected products include: Getoutline Outline.