CVE-2020-7776 Explained : Impact and Mitigation

This CVE-2020-7776 article provides insights into a Cross-site Scripting (XSS) vulnerability affecting phpoffice/phpspreadsheet.

Understanding CVE-2020-7776

This section delves into the details of the CVE-2020-7776 vulnerability.

What is CVE-2020-7776?

CVE-2020-7776 is a Cross-site Scripting (XSS) vulnerability found in the phpoffice/phpspreadsheet package version 0.0.0. It allows attackers to execute malicious scripts in a victim's browser.

The Impact of CVE-2020-7776

The vulnerability has a CVSS base score of 7.1, indicating a high severity level. It can lead to unauthorized access to sensitive information and compromise data integrity.

Technical Details of CVE-2020-7776

This section provides technical insights into the CVE-2020-7776 vulnerability.

Vulnerability Description

The XSS vulnerability in phpoffice/phpspreadsheet arises when creating an HTML output from an Excel file by adding a comment to any cell. The issue lies in the HTML writer, where user comments are concatenated as part of a link, resulting in HTML output.

Affected Systems and Versions

Affected Package: phpoffice/phpspreadsheet
Vulnerable Version: 0.0.0

Exploitation Mechanism

The vulnerability can be exploited by crafting a specially designed Excel file with malicious comments that, when processed, execute unauthorized scripts in the context of the user's session.

Mitigation and Prevention

Learn how to mitigate and prevent the CVE-2020-7776 vulnerability.

Immediate Steps to Take

Update the phpoffice/phpspreadsheet package to a non-vulnerable version.
Avoid opening Excel files from untrusted sources.

Long-Term Security Practices

Regularly update software packages to patch known vulnerabilities.
Educate users on safe handling of files from external sources.

Patching and Updates

Apply the fix available on commit 0ed5b800be2136bcb8fa9c1bdf59abc957a98845/master branch to address the XSS vulnerability in phpoffice/phpspreadsheet.