GHSA-GXX4-3XCV-F8QX

Vulnerability from github – Published: 2026-06-15 17:21 – Updated: 2026-06-15 17:21
VLAI
Summary
@angular/platform-server: Missing `<noscript>` Raw-Text Serialization Escaping leads to Cross-Site Scripting (XSS) in Angular SSR
Details

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

When rendering dynamic text content inside a <noscript> element via template bindings (such as {{ value }} or [textContent]), the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), domino is configured with scripting enabled, meaning <noscript> is treated as a raw-text element.

However, domino's serializer completely omitted <noscript> from the list of raw-text elements requiring closing-tag escaping during DOM serialization. As a result, any occurrence of </noscript> in the bound dynamic text was never escaped under any circumstances.

The unescaped closing tag was serialized directly into the output HTML (e.g. <noscript></noscript><script>alert(1)</script></noscript>). When parsed by a browser, it closes the <noscript> block early, allowing the 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 a <noscript> element. This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.

Patched Versions

  • 22.0.0-rc.2
  • 21.2.16
  • 20.3.24
  • 19.2.25

Workarounds

If you cannot immediately update your dependencies, you can:

  • Avoid binding user-controlled values inside <noscript> elements.
  • Sanitize any user input placed inside <noscript> to explicitly strip closing </noscript> 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
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "22.0.0-next.0"
            },
            {
              "fixed": "22.0.0-rc.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "21.0.0-next.0"
            },
            {
              "fixed": "21.2.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0-next.0"
            },
            {
              "fixed": "20.3.24"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "19.0.0-next.0"
            },
            {
              "fixed": "19.2.25"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@angular/platform-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "18.2.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-50556"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-15T17:21:03Z",
    "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 `\u003cnoscript\u003e` elements.\n\nWhen rendering dynamic text content inside a `\u003cnoscript\u003e` element via template bindings (such as `{{ value }}` or `[textContent]`), the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), `domino` is configured with scripting enabled, meaning `\u003cnoscript\u003e` is treated as a raw-text element.\n\nHowever, `domino`\u0027s serializer completely omitted `\u003cnoscript\u003e` from the list of raw-text elements requiring closing-tag escaping during DOM serialization. As a result, any occurrence of `\u003c/noscript\u003e` in the bound dynamic text was **never escaped under any circumstances**.\n\nThe unescaped closing tag was serialized directly into the output HTML (e.g. `\u003cnoscript\u003e\u003c/noscript\u003e\u003cscript\u003ealert(1)\u003c/script\u003e\u003c/noscript\u003e`). When parsed by a browser, it closes the `\u003cnoscript\u003e` block early, allowing the injected `\u003cscript\u003e` 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 a `\u003cnoscript\u003e` element. This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.\n\n### Patched Versions\n\n- 22.0.0-rc.2\n- 21.2.16\n- 20.3.24\n- 19.2.25\n\n### Workarounds\n\nIf you cannot immediately update your dependencies, you can:\n\n- Avoid binding user-controlled values inside `\u003cnoscript\u003e` elements.\n- Sanitize any user input placed inside `\u003cnoscript\u003e` to explicitly strip closing `\u003c/noscript\u003e` tags before passing it to the template.",
  "id": "GHSA-gxx4-3xcv-f8qx",
  "modified": "2026-06-15T17:21:03Z",
  "published": "2026-06-15T17:21:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/security/advisories/GHSA-gxx4-3xcv-f8qx"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/angular/issues/68903"
    },
    {
      "type": "WEB",
      "url": "https://github.com/angular/domino/pull/29"
    },
    {
      "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/platform-server: Missing `\u003cnoscript\u003e` Raw-Text Serialization Escaping leads to Cross-Site Scripting (XSS) in Angular SSR"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.