GHSA-48r7-hpm6-gfxm @angular/common: Denial of Service (DoS) via OOM in Date Formatting (formatDate)

• npm @angular/common: >= 22.0.0-next.0, < 22.0.1 → fixed in 22.0.1 • npm @angular/common: >= 21.0.0-next.0, < 21.2.17 → fixed in 21.2.17 • npm @angular/common: >= 20.0.0-next.0, < 20.3.25 → fixed in 20.3.25 • npm @angular/common: <= 19.2.25 (no fix yet)

A Denial of Service (DoS) vulnerability exists in the `@angular/common` package of the Angular framework. The `formatDate` function, which is also utilized by the standard Angular `DatePipe`, does not properly limit or validate the length of the `format` parameter. When parsing a maliciously crafted, excessively long date format string (e.g., a repeating pattern or very large string), the internal parser splits the string iteratively using a regular expression loop. This results in uncontrolled resource consumption (high CPU utilization and excessive memory allocations), leading to a Denial of Service (DoS). Impact 1. Server-Side Rendering (SSR) In Angular applications that leverage Server-Side Rendering, an attacker can supply a malicious payload with an excessively long date format string. Processing this on the server causes high CPU usage and triggers a `JavaScript heap out of memory` crash, rendering the application unavailable to all users. 2. Client-Side Rendering (CSR) In standard client-side applications, executing the vulnerable function with an excessively long format string blocks the browser's main thread, causing the browser tab to freeze and become completely unresponsive. Patched Versions • 22.0.1 • 21.2.17 • 20.3.25 Attack Preconditions For this vulnerability to be exploitable, both of the following conditions must be met: 1. Vulnerable Component Usage: The application must format dates using the `formatDate` utility or the `DatePipe`. 2. Attacker-Controlled Parameter: The date format string passed to these utilities must be customizable or directly controlled by untrusted user input (e.g., parsed from query parameters, user preferences, or API responses). *If the date format is hardcoded (e.g., `'mediumDate'`, `'shortTime'`, or static strings) or properly validated to be within a reasonable length limit, the application is not vulnerable.*