CVE-2026-55210 — Joplin: SAML SSO account takeover via email-based account linking (missing is_external check in ssoLogin)
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 existin…
Published: 2026-09-21 · CVSS: 7.4 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7