Skip to content

fix(core): reject script element as a dynamic component host #68713

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
leonsenft merged 1 commit into from
May 18, 2026
+57 −0
Merged

fix(core): reject script element as a dynamic component host #68713

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 7 additions & 0 deletions packages/core/src/render3/instructions/shared.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ import {stringify} from '../../util/stringify';
import {assertFirstCreatePass, assertHasParent, assertLView} from '../assert';
import {attachPatchData} from '../context_discovery';
import {getNodeInjectable, getOrCreateNodeInjectorForNode} from '../di';
import {RuntimeError, RuntimeErrorCode} from '../../errors';
import {throwMultipleComponentError} from '../errors';
import {ComponentDef, ComponentTemplate, DirectiveDef, RenderFlags} from '../interfaces/definition';
import {
Expand Down Expand Up @@ -180,6 +181,12 @@ export function locateHostElement(
encapsulation === ViewEncapsulation.ShadowDom ||
encapsulation === ViewEncapsulation.ExperimentalIsolatedShadowDom;
const rootElement = renderer.selectRootElement(elementOrSelector, preserveContent);
if (rootElement.tagName.toLowerCase() === 'script') {

@SkyZeroZx SkyZeroZx May 13, 2026 •
edited
Loading

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Perhaps a simple way would be to prevent any child of the host from having a script (considering we are prohibiting scripts at both the compiler and SVG levels, which would be the overall and retroactive goal if any future HTML spec allows it).

function containsScriptElement(root: Element): boolean {
  return root.localName === 'script' || root.querySelector('script') !== null;
}

throw new RuntimeError(
RuntimeErrorCode.UNSAFE_VALUE_IN_SCRIPT,
ngDevMode && `"<script>" tag is not allowed as a component host element.`,
);
}
applyRootElementTransform(rootElement as HTMLElement);
return rootElement;
}
Expand Down
50 changes: 50 additions & 0 deletions packages/core/test/acceptance/security_spec.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,9 @@ import {NgIf} from '@angular/common';
import {DomSanitizer} from '@angular/platform-browser';
import {
Component,
createComponent,
Directive,
EnvironmentInjector,
inject,
provideZoneChangeDetection,
TemplateRef,
Expand Down Expand Up @@ -852,3 +854,51 @@ describe('innerHTML processing', () => {
expect(fixture.nativeElement.innerHTML).not.toContain('action');
});
});

describe('Component host element validation', () => {
it('should throw an error when dynamically mounting a component onto a script tag', () => {
@Component({
selector: 'my-sink',
template: '',
})
class MySink {}

const scriptHost = document.createElement('script');
document.head.appendChild(scriptHost);

try {
const environmentInjector = TestBed.inject(EnvironmentInjector);
expect(() => {
createComponent(MySink, {
environmentInjector,
hostElement: scriptHost,
});
}).toThrowError(/"<script>" tag is not allowed as a component host element/);
} finally {
scriptHost.remove();
}
});

it('should throw an error when dynamically mounting a component onto an SVG script tag', () => {
@Component({
selector: 'my-svg-sink',
template: '',
})
class MySvgSink {}

const svgScriptHost = document.createElementNS('http://www.w3.org/2000/svg', 'script');

@SkyZeroZx SkyZeroZx May 13, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I understand this; I would only validate that the host is a script.

We are not validating a case as if it were

<svg>
<script> </script>
</svg>

For example

It will not throw an error; it currently has the previously described form (and is also considered validated HTML according to https://developer.mozilla.org/en-US/docs/Web/API/SVGScriptElement)

    const svgHost = document.createElementNS(SVG_NS, 'svg');
    const text = document.createElementNS(SVG_NS, 'text');
    const script = document.createElementNS(SVG_NS, 'script');
    svgHost.append(text, script);
    this.ref = createComponent(SvgScriptChildPov, {
      environmentInjector: this.env,
      hostElement: svgHost,
    });

document.head.appendChild(svgScriptHost);

try {
const environmentInjector = TestBed.inject(EnvironmentInjector);
expect(() => {
createComponent(MySvgSink, {
environmentInjector,
hostElement: svgScriptHost,
});
}).toThrowError(/"<script>" tag is not allowed as a component host element/);
} finally {
svgScriptHost.remove();
}
});
});
Loading