Skip to content

fix(ssr): validate bq-style declarations in the pure renderer #196

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
JosunLP merged 3 commits into from
Jul 6, 2026
Merged

fix(ssr): validate bq-style declarations in the pure renderer #196

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5d5967d
fix(ssr): validate bq-style declarations in the pure renderer
JosunLP Jul 6, 2026
31360b3
Merge branch 'dev' into fix/176-bq-style-css-injection
JosunLP Jul 6, 2026
939a46a
test(ssr): fix merge artifact — close #176 bq-style describe block
JosunLP Jul 6, 2026
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
14 changes: 13 additions & 1 deletion src/ssr/renderer.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -137,13 +137,25 @@ const setClass = (el: SSRElement, cls: string): void => {
el.attributes['class'] = merged;
};

// A CSS property name: standard kebab-case identifiers or `--custom-props`.
const SAFE_STYLE_PROP = /^(?:--[\w-]+|-?[a-z][a-z0-9-]*)$/;
// Characters that would let an untrusted value break out of its declaration and
// inject additional declarations or rules.
const UNSAFE_STYLE_VALUE = /[;{}<]/;

const setStyle = (el: SSRElement, declarations: Record<string, unknown>): void => {
let css = el.attributes['style'] ?? '';
for (const [prop, val] of Object.entries(declarations)) {
if (val === undefined || val === null || val === false) continue;
const cssProp = prop.replace(/([A-Z])/g, '-$1').toLowerCase();
const value = String(val);
// Drop declarations whose property or value could inject extra CSS
// (e.g. a value like `x;} body{display:none`). The value is only
// attribute-escaped on serialize, which stops HTML breakout but not the
// injection of sibling declarations/rules within the style attribute.
if (!SAFE_STYLE_PROP.test(cssProp) || UNSAFE_STYLE_VALUE.test(value)) continue;
if (css && !css.endsWith(';')) css += '; ';
css += `${cssProp}: ${String(val)};`;
css += `${cssProp}: ${value};`;
}
if (!('style' in el.attributes)) el.attributeOrder.push('style');
el.attributes['style'] = css;
Expand Down
26 changes: 26 additions & 0 deletions tests/ssr-stable.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -478,6 +478,32 @@ describe('#129 resumable boundaries — client resume', () => {
});
});

describe('#176 bq-style CSS injection guard', () => {
for (const backend of BACKENDS) {
describe(`backend: ${backend}`, () => {
it('drops style values that try to inject extra declarations', () => {
withBackend(backend, () => {
const html = renderToString('<div bq-style="styles"></div>', {
styles: { width: 'x;} body{display:none' },
}).html;
expect(html).not.toContain('display:none');
expect(html).not.toContain('body{');
});
});

it('keeps safe style declarations', () => {
withBackend(backend, () => {
const html = renderToString('<div bq-style="styles"></div>', {
styles: { color: 'red', marginTop: '4px' },
}).html;
expect(html).toContain('color: red');
expect(html).toContain('margin-top: 4px');
});
});
});
}
});

describe('#163 bq-text escaping on raw-text elements', () => {
for (const backend of BACKENDS) {
describe(`backend: ${backend}`, () => {
Expand Down