Cybersecurity researchers have uncovered a critical flaw in the Marimo Notebook app that could allow attackers to execute malicious commands on users’ devices even when they are editing sensitive files. The vulnerability, which affects both Android and iOS versions of the app, highlights the importance of prioritizing security in popular productivity tools.
The issue arises from a privilege escalation bug that allows an attacker to run MCP (Mobile Command Protocol) commands before the notebook’s cells execute in edit mode. This means that even if a user has saved their notebook with sensitive information, such as login credentials or financial data, an attacker could potentially access and exploit it. The researchers discovered this flaw by analyzing the app’s code and identifying a weakness in its authorization mechanism.
The Marimo Notebook app is designed for collaborative note-taking and editing, allowing multiple users to work on the same document simultaneously. However, when a user saves their notebook with sensitive information, the app stores it locally on their device before syncing it with the cloud. An attacker could exploit this flaw by manipulating the saved notebook file, effectively bypassing the app’s security features.
The researchers demonstrated that an attacker could use this vulnerability to run arbitrary commands on the victim’s device, including accessing files and sending malicious data to external servers. This raises significant concerns for users who store sensitive information in their notebooks, such as financial or personal identifiable data. The affected devices are those running versions 3.5.2 and earlier of Marimo Notebook.
The researchers emphasize that this vulnerability is not unique to the Marimo Notebook app but rather a symptom of a broader problem: many popular productivity tools often prioritize ease of use over security features. This issue highlights the need for developers to implement robust security measures, such as data encryption and secure authorization mechanisms, in their apps. Users should exercise caution when storing sensitive information in cloud-based applications, especially those that offer collaborative features.
In light of this discovery, users are advised to update their Marimo Notebook app to the latest version (3.5.3) and ensure they have enabled two-factor authentication for their account. Furthermore, users should consider using secure note-taking apps that prioritize data encryption and authorization mechanisms. By being aware of these security risks and taking proactive measures, users can protect themselves from potential cyber threats.
Source: The Hacker News — 2026-08-25