CVE-2023-48302 : Vulnerability Insights and Analysis

Nextcloud Server is vulnerable to Self XSS when pasting HTML into the Text app with Ctrl+Shift+V.

Understanding CVE-2023-48302

This CVE identifies a vulnerability in Nextcloud Server that allows for a Self XSS exploit when inserting HTML code into the Text app using Ctrl+Shift+V.

What is CVE-2023-48302?

Nextcloud Server versions prior to 25.0.13, 26.0.8, and 27.1.3 are susceptible to a security flaw where pasting HTML code without markup results in rendered markup.

The Impact of CVE-2023-48302

This vulnerability could be exploited by an attacker to execute malicious scripts in the context of the victim's session, potentially leading to unauthorized actions or data theft.

Technical Details of CVE-2023-48302

This section delves into the specifics of the vulnerability.

Vulnerability Description

In affected versions of Nextcloud Server, incorrect rendering of HTML code pasted using Ctrl+Shift+V could enable Cross-Site Scripting attacks.

Affected Systems and Versions

Nextcloud Server versions >= 25.0.0, < 25.0.13, >= 26.0.0, < 26.0.8, and >= 27.0.0, < 27.1.3 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can leverage this flaw to trick users into pasting HTML code, which when rendered, can carry out malicious actions.

Mitigation and Prevention

To address CVE-2023-48302, immediate actions and long-term security practices are crucial.

Immediate Steps to Take

Users are advised to upgrade Nextcloud Server and Nextcloud Enterprise Server to versions 25.0.13, 26.0.8, or 27.1.3. Additionally, disabling the app text can serve as a temporary workaround.

Long-Term Security Practices

Practicing caution while copying and pasting content, especially HTML code, and staying updated on security patches and advisories can help mitigate such vulnerabilities.

Patching and Updates

Regularly check for security updates released by Nextcloud and promptly apply patches to mitigate the risk of exploitation.