CVE-2021-38507 : Vulnerability Insights and Analysis

A detailed overview of CVE-2021-38507, focusing on the Opportunistic Encryption vulnerability affecting Mozilla products.

Understanding CVE-2021-38507

This section delves into the description, impact, technical details, and mitigation strategies related to CVE-2021-38507.

What is CVE-2021-38507?

The Opportunistic Encryption feature of HTTP2 (RFC 8164) in Mozilla products allowed a network attacker to bypass Same-Origin-Policy, impacting Firefox, Thunderbird, and Firefox ESR versions less than 94, 91.3, and 91.3 respectively.

The Impact of CVE-2021-38507

This vulnerability enabled attackers to forward connections on different ports, tricking the browser into treating encrypted content as same-origin with unencrypted content on HTTP.

Technical Details of CVE-2021-38507

Explore the vulnerability description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The flaw allowed a connection to be upgraded to TLS while maintaining the appearance of an HTTP connection, potentially leading to security risks.

Affected Systems and Versions

Mozilla Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3 were vulnerable to this exploit.

Exploitation Mechanism

By leveraging the Opportunistic Encryption feature, malicious actors could breach the Same-Origin-Policy, posing a threat to user data security.

Mitigation and Prevention

Learn about the necessary steps to secure systems and prevent exploitation of CVE-2021-38507.

Immediate Steps to Take

Users are advised to update affected browsers and email clients to versions beyond the vulnerable releases.

Long-Term Security Practices

Enforcing HTTPS protocols and regular security updates can enhance overall system security and protect against similar vulnerabilities.

Patching and Updates

Stay informed about security patches released by Mozilla, ensuring timely application to address known vulnerabilities.