CVE-2021-46743: google firebase_php-jwt Type Confusion

Vulnerability summary

CVE-2021-46743 is a critical (CVSS 9.1) Type Confusion vulnerability in google firebase_php-jwt. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 55.7% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 29-03-2022
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

In Firebase PHP-JWT before 6.0.0, an algorithm-confusion issue (e.g., RS256 / HS256) exists via the kid (aka Key ID) header, when multiple types of keys are loaded in a key ring. This allows an attacker to forge tokens that validate under the incorrect key. NOTE: this provides a straightforward way to use the PHP-JWT library unsafely, but might not be considered a vulnerability in the library itself.

• CWE-843Access of Resource Using Incompatible Type ('Type Confusion')The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.