Angular SSR Vulnerability Allows Attackers to Access Sensitive Data

A high vulnerability in Angular’s server-side rendering (SSR) feature can lead to sensitive data exposure when multiple requests are handled at the same time.

This flaw, tracked as CVE-2025-59052, stems from a global race condition in the platform injector that may cause cross-request data leakage.

Organizations using vulnerable Angular versions should update immediately or implement recommended workarounds to avoid potential data breaches.

Vulnerability Details

Angular’s SSR uses a dependency injection container called the platform injector to store request-specific data during rendering.

Historically, this container was defined as a module-scoped global variable. When two or more rendering requests occur concurrently, they can share or overwrite this global injector state.

As a result, information intended for one user’s session such as authentication tokens, user-specific settings, or database query results could appear in another user’s response.

Attackers with network access could exploit this flaw by sending repeated SSR requests and inspecting the rendered pages or response headers, looking for data that belongs to other sessions.

As per the report, this vulnerability requires no special privileges or user interaction, making it both easy to exploit and dangerous in high-traffic applications.

Several Angular APIs relied on the previous behavior of the platform injector and require changes in server environments.

The bootstrapApplication function used by standalone applications now demands an explicit BootstrapContext argument to ensure the correct injector is used per request.

Likewise, getPlatform no longer returns the last created platform instance on the server, always returning null instead.

The destroyPlatform function has been converted into a no-op when called during SSR. Angular’s patch releases introduce these breaking changes only for server code. A new argument for bootstrapApplication must be added:

// Before:

const bootstrap = () => bootstrapApplication(AppComponent, config);

// After:

const bootstrap = (context: BootstrapContext) =>
  bootstrapApplication(AppComponent, config, context);

Angular provides automatic schematics to apply these code adjustments via ng update for versions 18, 19, and 20.

The issue is fixed in all active Angular release lines, including prerelease versions. Developers should upgrade to @angular/platform-server 18.2.14, 19.2.15, 20.3.0, or 21.0.0-next.3, and upgrade corresponding @angular/ssr and @nguniversal/common packages as applicable.

Until patches are in place, teams can disable SSR using server routing or builder options, remove asynchronous behavior from custom bootstrap functions, eliminate calls to getPlatform(), and force jit mode off in server builds.

These mitigations reduce the risk of leaking platform injector state across requests.

CVE-2025-59052 highlights the complexity of server-side frameworks and the importance of isolating per-request data.

By applying official updates or following recommended workarounds, developers can secure their Angular SSR deployments against this high-severity flaw and maintain the privacy of user data.

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