🛡️ CVE-2026-33640 — outline

🔴 CVSS 9.8 — Critical ⚠️ Exploit Public CWE-307 NVD
9.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-33640 is classified as CWE-307: Improper Restriction of Excessive Authentication Attempts. Repeated login attempts are not limited, leaving credentials open to brute forcing.

Affected software

CVE-2026-33640 is recorded against 1 package.

  • outline (from 0.86.0 up to 1.6.0)

Timeline and source

Published on 26 March 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from NVD.

References

github.com
github.com

Details

Severity CRITICAL
CVSS Score 9.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-307
Public Exploit ⚠️ Yes
Source NVD
Published 2026-03-26
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
outline 0.86.0 1.6.0

Similar Threats

Exploit Protection

Are you running outline?

CVE-2026-33640 carries CVSS 9.8 Critical rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

Check My Site For CVE-2026-33640 →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.