Angular SSR route-policy confusion can expose client-only data under public cache headers

[SkyZeroZx]

Description

Angular SSR can select server-route metadata from one route while Angular Router renders a different route when the request URL contains certain ambiguous path forms.

Example:

/profile;
/profile//public

In both cases, a route configured as RenderMode.Client can be unexpectedly rendered on the server while inheriting public cache headers from another ServerRoute.

Minimal Reproduction

Minimal configuration

import { RenderMode, ServerRoute } from '@angular/ssr';

export const serverRoutes: ServerRoute[] = [
  {
    path: 'profile',
    renderMode: RenderMode.Client,
    headers: {
      'Cache-Control': 'private, no-store',
    },
  },
  {
    path: 'profile/public',
    renderMode: RenderMode.Server,
    headers: {
      'Cache-Control': 'public, max-age=300',
    },
  },
  {
    path: '**',
    renderMode: RenderMode.Server,
    headers: {
      'Cache-Control': 'public, max-age=300',
    },
  },
];

The /profile component reads a benign request-derived marker through the SSR REQUEST token.

Steps to reproduce

Request the normal client-only route:

curl -i \
  -H 'Cookie: session=PRIVATE_VALUE' \
  http://localhost:4000/profile

The initial HTML does not contain the request-derived value.

Request either crafted path:

curl -i \
  -H 'Cookie: session=PRIVATE_VALUE' \
  'http://localhost:4000/profile;'

curl -i \
  -H 'Cookie: session=PRIVATE_VALUE' \
  http://localhost:4000/profile//public

Actual behavior

The crafted requests can:

• render the /profile component on the server;
• expose request-derived data in the initial HTML;
• apply Cache-Control: public metadata belonging to another server route.

Expected behavior

The route used to select renderMode, status, and response headers must always correspond to the route whose body is rendered.

A route configured as RenderMode.Client should not be server-rendered through an alternative URL representation.

Your Environment

Angular 22.X

Anything else relevant?

This was previously reported at https://issuetracker.google.com/u/1/issues/518988455