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

Type: advisorySource: OSV1 source record

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`). 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**. ### Impact Successful exploitation allows an unauthenticated remote attacker to exhaust the Node.js old-space heap with modest request volume, terminating the SSR worker with an unrecoverable `JavaScript heap out of memory` fatal error and causing a Denial of Service. * **High Amplification:** A single 11-b

Announced Source revision 1
Original source ↗

GHSA-ff3f-86qr-9cv3

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:GHSA-ff3f-86qr-9cv3

@angular/router

Source reference: /affected/0/package/name

Affected versions
Not stated in this record
Fixed versions
22.2.0

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

@angular/router

Source reference: /affected/1/package/name

Affected versions
Not stated in this record
Fixed versions
21.2.24

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

@angular/router

Source reference: /affected/2/package/name

Affected versions
Not stated in this record
Fixed versions
20.3.32

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

@angular/router

Source reference: /affected/3/package/name

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "22.0.0"
          },
          {
            "fixed": "22.2.0"
          }
        ]
      }
    ],
    "package": {
      "name": "@angular/router",
      "purl": "pkg:npm/%40angular/router",
      "ecosystem": "npm"
    },
    "database_specific": {
      "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-ff3f-86qr-9cv3/GHSA-ff3f-86qr-9cv3.json"
    }
  },
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "21.0.0"
          },
          {
            "fixed": "21.2.24"
          }
        ]
      }
    ],
    "package": {
      "name": "@angular/router",
      "purl": "pkg:npm/%40angular/router",
      "ecosystem": "npm"
    },
    "database_specific": {
      "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-ff3f-86qr-9cv3/GHSA-ff3f-86qr-9cv3.json"
    }
  },
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "20.0.0"
          },
          {
            "fixed": "20.3.32"
          }
        ]
      }
    ],
    "package": {
      "name": "@angular/router",
      "purl": "pkg:npm/%40angular/router",
      "ecosystem": "npm"
    },
    "database_specific": {
      "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-ff3f-86qr-9cv3/GHSA-ff3f-86qr-9cv3.json"
    }
  },
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "0"
          },
          {
            "last_affected": "19.2.25"
          }
        ]
      }
    ],
    "package": {
      "name": "@angular/router",
      "purl": "pkg:npm/%40angular/router",
      "ecosystem": "npm"
    },
    "database_specific": {
      "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-ff3f-86qr-9cv3/GHSA-ff3f-86qr-9cv3.json"
    }
  }
]
Related CVEs
CVE-2026-101896

Source reference: /aliases

Publisher severity

high

Source reference: /database_specific/severity

Linked CVE context

These ratings describe the referenced vulnerabilities and products. They are not a severity rating for every application using this dependency.

CVE-2026-101896 · High

angular, router

Event
#39382 · Revision 1
Added to Heist Feed
Publisher date
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