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fix(ssr): escape bq-text values on raw-text elements in pure renderer #183

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Merged
JosunLP merged 2 commits into from
Jul 6, 2026
Merged

fix(ssr): escape bq-text values on raw-text elements in pure renderer #183

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62dac40
fix(ssr): escape bq-text values on raw-text elements in pure renderer
JosunLP Jul 6, 2026
8af1b09
Merge branch 'dev' into fix/163-ssr-bq-text-raw-escape
JosunLP Jul 6, 2026
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10 changes: 5 additions & 5 deletions src/ssr/renderer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -193,7 +193,10 @@ const stripDirectiveAttributes = (node: SSRNode, prefix: string): void => {
};

const setText = (el: SSRElement, value: string): void => {
el.children = [{ type: 'text', value }];
// Raw-text elements (script/style/textarea/title) are serialized verbatim
// by serializeTree, so escape here or a value like `</textarea><script>…`
// would break out of the element (XSS).
el.children = [{ type: 'text', value: el.raw ? escapeText(value) : value }];
};

/** Recursively collects `<option>` descendants of a virtual `<select>`. */
Expand Down Expand Up @@ -232,10 +235,7 @@ const applyModelToPureElement = (el: SSRElement, value: unknown): void => {
else removeAttr(el, reflection.name);
break;
case 'text':
// textarea is a raw-text element, so serializeTree emits its text
// children verbatim. Escape the reflected value here or a model value
// like `</textarea><script>…` would break out of the element (XSS).
setText(el, el.raw ? escapeText(reflection.value) : reflection.value);
setText(el, reflection.value);
break;
case 'select': {
const options: SSRElement[] = [];
Expand Down
35 changes: 35 additions & 0 deletions tests/ssr-stable.test.ts
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Expand Up @@ -477,3 +477,38 @@ describe('#129 resumable boundaries — client resume', () => {
expect(result.wiredHandlers).toBe(0);
});
});

describe('#163 bq-text escaping on raw-text elements', () => {
for (const backend of BACKENDS) {
describe(`backend: ${backend}`, () => {
it('escapes bq-text values inside <textarea>', () => {
withBackend(backend, () => {
const html = renderToString('<textarea bq-text="msg"></textarea>', {
msg: '</textarea><img src=x onerror=alert(1)>',
}).html;
expect(html).not.toContain('<img');
expect(html).toContain('&lt;/textarea&gt;');
});
});

it('escapes bq-text values inside <title>', () => {
withBackend(backend, () => {
const html = renderToString('<title bq-text="msg"></title>', {
msg: '</title><script>alert(1)</script>',
}).html;
expect(html).not.toContain('<script>');
});
});

it('leaves bq-text on normal elements escaped exactly once', () => {
withBackend(backend, () => {
const html = renderToString('<p bq-text="msg"></p>', {
msg: '<b>&amp;</b>',
}).html;
expect(html).toContain('&lt;b&gt;');
expect(html).not.toContain('&amp;amp;amp;');
});
});
});
}
});