Security Flaw in 2FAuth Web App for Two-Factor Authentication Management

CVE-2026-63440

What is CVE-2026-63440?

The 2FAuth web application, designed for managing Two-Factor Authentication accounts, contains a flaw in its handling of external otpauth image fetching. Prior to version 8.0.0, an authenticated user could exploit the image-fetch path's validation mechanism. This vulnerability allowed the user to manipulate DNS resolution, facilitating a potential bypass of security measures against accessing internal hosts. By returning a public address during the initial validation and an internal address when establishing a connection, attackers could access sensitive internal network resources. This issue has been addressed in version 8.0.0, enhancing the security of the application.

References