GHSA-VPX6-8PJR-4G3V

Vulnerability from github – Published: 2026-08-03 16:14 – Updated: 2026-08-03 16:14
VLAI
Summary
Angular SSR: Missing Fallback Raw-Content Serialization Escaping leads to Cross-Site Scripting (XSS)
Details

A Cross-Site Scripting (XSS) vulnerability exists in @angular/platform-server's DOM emulation dependency (domino) when serializing the content of fallback raw-content elements (<iframe>, <noembed>, <noframes>, and <noscript>).

When rendering dynamic text content inside fallback raw-content elements via template bindings, the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), domino is configured with scripting enabled, meaning these elements are treated as raw-text elements.

However, domino's serializer previously did not escape text nodes within fallback raw-content elements (<iframe>, <noembed>, <noframes>, <noscript>) during DOM serialization. As a result, any occurrence of closing tags in the bound dynamic text was not escaped.

The unescaped closing tag could be serialized directly into the output HTML. When parsed by a browser or re-parsed during SSR post-processing without preserving raw-content parser state, an injected closing tag closes the element early, allowing an injected script block to execute in the user's browser context, causing same-origin Cross-Site Scripting (XSS).

Impact

This vulnerability allows an attacker to perform same-origin Cross-Site Scripting (XSS) attacks against any user visiting an SSR-rendered page that binds user-controlled data inside fallback raw-content elements (<iframe>, <noembed>, <noframes>, <noscript>). This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.

Patched Versions

  • 22.0.7
  • 21.2.19
  • 20.3.27

Workarounds

If you cannot immediately update your dependencies, you can mitigate this issue using any of the following approaches: - Disable critical CSS inlining: Critical CSS inlining in Angular SSR post-processes the rendered HTML using domino. Disabling this step prevents domino from re-parsing and re-serializing the HTML during server-side rendering. - In angular.json, set inlineCritical to false under style optimization options: json { "projects": { "my-app": { "architect": { "build": { "builder": "@angular/build:application", "options": { "optimization": { "styles": { "inlineCritical": false } } } } } } } } - When rendering programmatically with CommonEngine, set inlineCriticalCss: false in your render options. - Avoid binding user-controlled values inside fallback raw-content elements (<iframe>, <noembed>, <noframes>, <noscript>). - Sanitize user input placed inside these elements to explicitly strip or escape closing tags before passing it to the template.

Severity
8.6 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "22.0.0-next.0"
            },
            {
              "fixed": "22.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "21.0.0-next.0"
            },
            {
              "fixed": "21.2.19"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0-next.0"
            },
            {
              "fixed": "20.3.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "19.2.25"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-69149"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-03T16:14:43Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "A Cross-Site Scripting (XSS) vulnerability exists in `@angular/platform-server`\u0027s DOM emulation dependency (`domino`) when serializing the content of fallback raw-content elements (`\u003ciframe\u003e`, `\u003cnoembed\u003e`, `\u003cnoframes\u003e`, and `\u003cnoscript\u003e`).\n\nWhen rendering dynamic text content inside fallback raw-content elements via template bindings, the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), `domino` is configured with scripting enabled, meaning these elements are treated as raw-text elements.\n\nHowever, `domino`\u0027s serializer previously did not escape text nodes within fallback raw-content elements (`\u003ciframe\u003e`, `\u003cnoembed\u003e`, `\u003cnoframes\u003e`, `\u003cnoscript\u003e`) during DOM serialization. As a result, any occurrence of closing tags in the bound dynamic text was not escaped.\n\nThe unescaped closing tag could be serialized directly into the output HTML. When parsed by a browser or re-parsed during SSR post-processing without preserving raw-content parser state, an injected closing tag closes the element early, allowing an injected script block to execute in the user\u0027s browser context, causing same-origin Cross-Site Scripting (XSS).\n\n### Impact\n\nThis vulnerability allows an attacker to perform same-origin Cross-Site Scripting (XSS) attacks against any user visiting an SSR-rendered page that binds user-controlled data inside fallback raw-content elements (`\u003ciframe\u003e`, `\u003cnoembed\u003e`, `\u003cnoframes\u003e`, `\u003cnoscript\u003e`). This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.\n\n### Patched Versions\n\n- 22.0.7\n- 21.2.19\n- 20.3.27\n\n### Workarounds\nIf you cannot immediately update your dependencies, you can mitigate this issue using any of the following approaches:\n- **Disable critical CSS inlining**: Critical CSS inlining in Angular SSR post-processes the rendered HTML using `domino`. Disabling this step prevents `domino` from re-parsing and re-serializing the HTML during server-side rendering.\n  - In `angular.json`, set `inlineCritical` to `false` under style optimization options:\n    ```json\n    {\n      \"projects\": {\n        \"my-app\": {\n          \"architect\": {\n            \"build\": {\n              \"builder\": \"@angular/build:application\",\n              \"options\": {\n                \"optimization\": {\n                  \"styles\": {\n                    \"inlineCritical\": false\n                  }\n                }\n              }\n            }\n          }\n        }\n      }\n    }\n    ```\n  - When rendering programmatically with `CommonEngine`, set `inlineCriticalCss: false` in your render options.\n- **Avoid binding user-controlled values** inside fallback raw-content elements (`\u003ciframe\u003e`, `\u003cnoembed\u003e`, `\u003cnoframes\u003e`, `\u003cnoscript\u003e`).\n- **Sanitize user input** placed inside these elements to explicitly strip or escape closing tags before passing it to the template.",
  "id": "GHSA-vpx6-8pjr-4g3v",
  "modified": "2026-08-03T16:14:43Z",
  "published": "2026-08-03T16:14:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/security/advisories/GHSA-vpx6-8pjr-4g3v"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/pull/69675"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/pull/69714"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/pull/69929"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/pull/69930"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/domino/pull/32"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/domino/commit/f88e5aa49cf2804d7c2df22ef1640eb4ec43dd56"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/angular/angular"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Angular SSR: Missing Fallback Raw-Content Serialization Escaping leads to Cross-Site Scripting (XSS)"
}



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