CVE-2021-39307 : Vulnerability Insights and Analysis

PDFTron's WebViewer UI 8.0 or below is vulnerable to rendering dangerous URLs as hyperlinks in supported documents, potentially leading to the execution of arbitrary JavaScript code.

Understanding CVE-2021-39307

This CVE involves a security vulnerability in PDFTron's WebViewer UI versions 8.0 and below that allows the inclusion of dangerous URLs as hyperlinks in documents.

What is CVE-2021-39307?

PDFTron's WebViewer UI 8.0 or below renders dangerous URLs as hyperlinks in supported documents, including JavaScript URLs, allowing the execution of arbitrary JavaScript code.

The Impact of CVE-2021-39307

The vulnerability could be exploited by an attacker to execute arbitrary JavaScript code within the context of the user's browser, potentially leading to unauthorized actions or data theft.

Technical Details of CVE-2021-39307

PDFTron's WebViewer UI vulnerability exposes users to the execution of arbitrary JavaScript code through malicious URLs.

Vulnerability Description

In versions 8.0 and below, WebViewer UI does not properly handle dangerous URLs, rendering them as clickable links in documents. This could enable an attacker to craft a document containing a malicious link that, when clicked, executes arbitrary JavaScript code.

Affected Systems and Versions

Product: PDFTron WebViewer UI
Version: 8.0 and below

Exploitation Mechanism

The vulnerability is exploited by embedding a JavaScript URL within a document that, when clicked by a user, triggers the execution of the malicious code within the user's browser environment.

Mitigation and Prevention

To address CVE-2021-39307, users and organizations should take immediate and long-term security measures to protect against potential exploitation.

Immediate Steps to Take

Upgrade PDFTron's WebViewer UI to a secure version that includes a fix for the vulnerability.
Avoid clicking on links from untrusted or suspicious documents.
Consider disabling JavaScript execution in the PDF viewer settings as a temporary measure.

Long-Term Security Practices

Regularly update software components to the latest secure versions.
Conduct security assessments and audits of third-party components integrated into software applications.

Patching and Updates

PDFTron has likely released a patch or updated version to address the vulnerability. Ensure timely installation of updates to mitigate the risk of exploitation.