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 ↗

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

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

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