Joplin: SAML SSO account takeover via email-based account linking (missing is_external check in ssoLogin)
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-290.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA joplin (laurent22) Fixed in 3.7.2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-55210
References
More laurent22 vulnerabilities
- TI-2023-24472 Arbitrary code execution on click of PDF links in Joplin CVSS 3.1CRITICAL 9.0
- TI-2024-32950 Remote Code Execution on click of <a> Link in markdown preview CVSS 3.1CRITICAL 9.6
- TI-2024-27054 Joplin has a parsing error leading to Cross-site Scripting (XSS) CVSS 3.1CRITICAL 9.7
- TI-2026-34297 Joplin: SSO Auth Code Login Missing Rate Limiting — 9-Digit Numeric Code Brute-Forceable via Unprotected Endpoint CVSS 4.0CRITICAL 9.1
- TI-2025-17795 Cross-site Scripting (XSS) in Rich Text Editor allows arbitrary code execution in Joplin CVSS 3.1CRITICAL 9.6
- TI-2025-19991 Privilege escalation in Joplin server via user patch endpoint CVSS 3.1HIGH 8.8
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences