AI Threat Alert
CVE-2026-55210
HIGHJoplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.2, Joplin Server's UserModel.ssoLogin() returns an existing account matched by an IdP-asserted email without checking the account's is_external flag. In deployments using mixed...
Full CISO analysis pending enrichment.
How severe is it?
What is the attack surface?
What should I do?
No patch available
Monitor for updates. Consider compensating controls or temporary mitigations.
Which compliance frameworks are affected?
Compliance analysis pending. Sign in for full compliance mapping when available.
Frequently Asked Questions
What is CVE-2026-55210?
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.2, Joplin Server's UserModel.ssoLogin() returns an existing account matched by an IdP-asserted email without checking the account's is_external flag. In deployments using mixed local and SAML authentication, an attacker whose IdP session can assert a local user's email can pass POST /api/saml, receive a session for that local account, and access or modify the victim's notes, files, and settings without knowing the local password. This issue is fixed in version 3.7.2.
Is CVE-2026-55210 actively exploited?
No confirmed active exploitation of CVE-2026-55210 has been reported, but organizations should still patch proactively.
How to fix CVE-2026-55210?
No patch is currently available. Monitor vendor advisories for updates.
What is the CVSS score for CVE-2026-55210?
CVE-2026-55210 has a CVSS v3.1 base score of 7.4 (HIGH).
What are the technical details?
Original Advisory
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.2, Joplin Server's UserModel.ssoLogin() returns an existing account matched by an IdP-asserted email without checking the account's is_external flag. In deployments using mixed local and SAML authentication, an attacker whose IdP session can assert a local user's email can pass POST /api/saml, receive a session for that local account, and access or modify the victim's notes, files, and settings without knowing the local password. This issue is fixed in version 3.7.2.
Weaknesses (CWE)
CWE-290 — Authentication Bypass by Spoofing: This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
Source: MITRE CWE corpus.
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N