CVE-2026-101896: Angular Server-Side Rendering (SSR): Denial of Service via Numeric URL Matrix Parameters

A denial of service (DoS) vulnerability was identified in @angular/router when Server-Side Rendering (SSR) is enabled on Node.js (V8).

When @angular/router parses incoming request URLs, it extracts path segments, matrix parameters, and child outlets into plain JavaScript objects (Record<string, string>). When matrix parameter names or outlet names are numeric strings (such as /a;990;2522), the V8 JavaScript engine interprets them as array-indexed properties rather than named properties.

Under V8’s internal property-storage heuristics, setting numeric keys on an initially empty object causes V8 to allocate a dense array backing store (HOLEY_ELEMENTS) sized to the maximum index rather than falling back to sparse dictionary storage. Specifically, assigning sequential or moderately large numeric keys (like 990 followed by 2522) causes V8 to allocate a contiguous backing store of ~2,522 pointers (~20 KB to 25 KB of heap) for a single 11-byte segment.

Because each segment in a URL path allocates its own independent parameters object, an attacker can craft URLs with repeated numeric matrix parameters to achieve an asymmetric memory amplification factor of approximately ~350x.