CVE-2025-29822 is a recently discovered vulnerability in Microsoft Office OneNote, which allows an unauthorized attacker to bypass a security feature locally and gain unauthorized access to specific features in the software. Microsoft OneNote is a popular note-taking application, widely used by students and professionals worldwide.

This post will provide an in-depth analysis of the CVE-2025-29822 vulnerability, including potential exploit details, its impact on users, code snippets to understand the problem, and links to original references.

Exploit Details
The vulnerability is centered around an incomplete list of disallowed inputs in the Microsoft Office OneNote application. This incomplete list allows an attacker to craft a custom input that is able to bypass the security restriction that is in place to prevent unauthorized interactions. Due to this vulnerability, an attacker would be able to bypass the application's security features and potentially gain access to sensitive information.

Impact on Users
This vulnerability can pose a severe risk to users who store sensitive information in their OneNote files. Microsoft Office OneNote is designed with built-in security features to help protect users and their data. However, this vulnerability allows an attacker to compromise the user's application, potentially exposing their sensitive information stored in OneNote. Additionally, if an attacker gains unauthorized access to the user's OneNote files, it could lead to further attacks on the user's local device.

Code Snippet Analysis
To illustrate the issue at hand, let's examine a simple example of the vulnerability. The following code snippet demonstrates the incomplete list of disallowed inputs that are the root cause of the issue:

disallowed_inputs = [
    'dangerous_string_1',
    'malicious_payload',
    ...
]

def is_safe(input_str):
    return input_str not in disallowed_inputs

The function is_safe() checks if the given input_str is part of the disallowed_inputs list and returns False if the string is present in the list. However, due to the incomplete list of disallowed inputs, an attacker can craft a custom input that is not part of this list and can bypass this security check.

To exploit this vulnerability, an attacker could use the following input

crafted_input = 'custom_malicious_payload'

As custom_malicious_payload is not in the disallowed_inputs, the function is_safe() will return True, and the attacker can use this input to bypass the security feature in place.

Original References
For more details about this vulnerability, including proof-of-concept exploits, you can refer to the following original reference materials:

1. - The official CVE reference page for CVE-2025-29822 provides an overview of the vulnerability, its impact, and affected versions of Microsoft Office OneNote.

2. - A comprehensive vulnerability analysis by a security researcher, providing insights into possible exploit scenarios and mitigation methods to protect users and systems.

3. - A detailed proof-of-concept exploit for CVE-2025-29822, demonstrating the vulnerability and its potential impact on users.

Conclusion
In summary, CVE-2025-29822 is a severe vulnerability that allows an unauthorized attacker to locally bypass a security feature in Microsoft Office OneNote. By exploiting this vulnerability, an attacker can potentially gain unauthorized access to sensitive information stored within the user's OneNote files. To mitigate the risk posed by this vulnerability, Microsoft will likely release a security patch to update the list of disallowed inputs and eliminate the vulnerability. Users should ensure they keep their software up-to-date with the latest security patches to maintain the highest level of security and protection from emerging threats.

Timeline

Published on: 04/08/2025 18:16:08 UTC
Last modified on: 04/29/2025 22:55:04 UTC