CVE-2020-15174: 
JavaScript vulnerability analysis and mitigation

CVE-2020-15174 is a security vulnerability discovered in Electron framework affecting versions before 11.0.0-beta.1, 10.0.1, 9.3.0, and 8.5.1. The vulnerability allows bypassing the 'will-navigate' event that applications use to prevent navigations to unexpected destinations when a sub-frame performs a top-frame navigation across sites (GitHub Advisory, NVD).

The vulnerability is classified as a Protection Mechanism Failure and Improper Input Validation with a CVSS v3.1 Base Score of 7.5 (HIGH). The issue stems from how Electron handles frame navigation, specifically when sub-frames attempt to perform top-frame navigation across different sites. The vulnerability allows bypassing the security mechanism that applications use to prevent unexpected navigations (Sonatype).

When exploited, this vulnerability could allow attackers to bypass navigation restrictions intended to protect users from being redirected to malicious sites. In applications like Discord that use Electron, this could be particularly dangerous as it could be chained with other vulnerabilities to achieve Remote Code Execution (RCE) on the user's system (CloudSEK).

The vulnerability can be exploited when a sub-frame performs a top-frame navigation across sites, effectively bypassing the intended security controls. This becomes particularly dangerous when chained with other vulnerabilities, such as XSS in iframe embeds, potentially leading to remote code execution (Sonatype).

The issue has been patched in Electron versions 11.0.0-beta.1, 10.0.1, 9.3.0, and 8.5.1. As a workaround, developers are advised to sandbox all iframes using the sandbox attribute, which prevents them from creating top-frame navigations and is considered good security practice (GitHub Advisory).