---
title: "CVE-2026-55210: Joplin Server - Authentication Bypass"
description: "Joplin Server < 3.7.2 contains an authentication bypass caused by UserModel.ssoLogin() returning accounts without checking is_external flag, letting attackers with IdP session access local user accounts, exploit requires IdP session asserting local user's email."
url: https://panop.io/threat-heartbeat/CVE-2026-55210/
---

# CVE-2026-55210 Joplin Server - Authentication Bypass

Joplin Server < 3.7.2 contains an authentication bypass caused by UserModel.ssoLogin() returning accounts without checking is\_external flag, letting attackers with IdP session access local user accounts, exploit requires IdP session asserting local user's email.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.48% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-55210)

## Details

Type

Authentication Bypass

Impact

Broken Authentication, Broken Access Control, Data Tampering, Information Disclosure

CVSS vector

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

Published

21 September 2026

Updated

15 October 2026

Weakness

[CWE-290](https://cwe.mitre.org/data/definitions/290.html)

## Vendor fix

Upgrade to version 3.7.2 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-55210](https://nvd.nist.gov/vuln/detail/CVE-2026-55210)
- [https://github.com/laurent22/joplin/commit/b6d69d072919cbe769234f93d95ed21e1ec129b2](https://github.com/laurent22/joplin/commit/b6d69d072919cbe769234f93d95ed21e1ec129b2)
- [https://github.com/laurent22/joplin/pull/15647](https://github.com/laurent22/joplin/pull/15647)
- [https://github.com/laurent22/joplin/security/advisories/GHSA-5px3-4f5x-hjc5](https://github.com/laurent22/joplin/security/advisories/GHSA-5px3-4f5x-hjc5)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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