CVE-2026-34600
Joplin Server delta API returns note content after share access is revoked
Description
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Versions 3.5.2 and prior contain a logic error in the delta API that allows share recipients to download notes that are no longer shared with them, related to but not fully fixed by the prior patch in #14289. In ChangeModel.delta, when DELTA_INCLUDES_ITEMS is enabled (the default), the latest state of items is attached to delta output without verifying that those items are still shared with the requesting user, and the existing removal logic only filters items deleted for all users. Additionally, the change compression logic incorrectly reduces create - delete to NOOP, which is unsafe because compression is applied per page and an item can have multiple create events; if an earlier create falls on a separate page from a later create -> delete pair, the deletion is dropped and the sequence collapses to a create. As a result, the delta API returns a create event for a deleted item with the full latest content attached, exposing notes the user no longer has access to. This issue has been fixed in version 3.5.3.
INFO
Published Date :
May 19, 2026, 11:16 p.m.
Last Modified :
July 24, 2026, 9:10 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Joplin to version 3.5.3 or later.
- Verify that the delta API correctly enforces sharing permissions.
- Ensure all shared items are properly removed when access is revoked.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-34600.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-34600 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-34600
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-34600 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-34600 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: Joplin de laurent22, Description: Joplin es una aplicación de toma de notas y de tareas pendientes de código abierto que organiza notas y listas en cuadernos. Las versiones 3.5.2 y anteriores contienen un error de lógica en la API delta que permite a los destinatarios de la compartición descargar notas que ya no están compartidas con ellos, relacionado con, pero no completamente solucionado por el parche anterior en el #14289. En ChangeModel.delta, cuando DELTA_INCLUDES_ITEMS está habilitado (el valor predeterminado), el estado más reciente de los elementos se adjunta a la salida delta sin verificar que esos elementos sigan compartidos con el usuario solicitante, y la lógica de eliminación existente solo filtra los elementos eliminados para todos los usuarios. Además, la lógica de compresión de cambios reduce incorrectamente create - delete a NOOP, lo cual es inseguro porque la compresión se aplica por página y un elemento puede tener múltiples eventos de creación; si una creación anterior cae en una página separada de un par posterior create -> delete, la eliminación se descarta y la secuencia se colapsa a una creación. Como resultado, la API delta devuelve un evento de creación para un elemento eliminado con el contenido completo más reciente adjunto, exponiendo notas a las que el usuario ya no tiene acceso. Este problema ha sido solucionado en la versión 3.5.3. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'laurent22', 'product': 'joplin', 'versions': [{'status': 'affected', 'version': '< 3.5.3'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-34600', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-20T14:10:05.523690Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 20, 2026
Action Type Old Value New Value Added Reference https://github.com/laurent22/joplin/security/advisories/GHSA-88x4-77rc-jw94 -
New CVE Received by [email protected]
May. 19, 2026
Action Type Old Value New Value Added Description Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Versions 3.5.2 and prior contain a logic error in the delta API that allows share recipients to download notes that are no longer shared with them, related to but not fully fixed by the prior patch in #14289. In ChangeModel.delta, when DELTA_INCLUDES_ITEMS is enabled (the default), the latest state of items is attached to delta output without verifying that those items are still shared with the requesting user, and the existing removal logic only filters items deleted for all users. Additionally, the change compression logic incorrectly reduces create - delete to NOOP, which is unsafe because compression is applied per page and an item can have multiple create events; if an earlier create falls on a separate page from a later create -> delete pair, the deletion is dropped and the sequence collapses to a create. As a result, the delta API returns a create event for a deleted item with the full latest content attached, exposing notes the user no longer has access to. This issue has been fixed in version 3.5.3. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N Added CWE CWE-200 Added CWE CWE-281 Added CWE CWE-863 Added Reference https://github.com/laurent22/joplin/issues/14110 Added Reference https://github.com/laurent22/joplin/pull/14289 Added Reference https://github.com/laurent22/joplin/security/advisories/GHSA-88x4-77rc-jw94