[SECURITY] Pin dependency svelte to 4.2.20

[lucca-renovate]

Description

This PR contains the following updates:

Package	Type	Update	Change
svelte (source)	devDependencies	pin	^4.2.19 → 4.2.20

⚠️ Renovate's pin functionality does not currently wire in the release age for a package, so the Minimum Release Age checks can apply. You will need to manually validate the Minimum Release Age for these package(s).

GitHub Vulnerability Alerts

CVE-2026-27121

Versions of svelte prior to 5.51.5 are vulnerable to cross-site scripting (XSS) during server-side rendering. When using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers.

CVE-2026-27122

When using <svelte:element this={tag}> in server-side rendering, the provided tag name is not validated or sanitized before being emitted into the HTML output. If the tag string contains unexpected characters, it can result in HTML injection in the SSR output. Client-side rendering is not affected.

CVE-2026-27125

In server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.

CVE-2026-27901

The contents of bind:innerText and bind:textContent on contenteditable elements were not properly escaped. This could enable HTML injection and Cross-site Scripting (XSS) if rendering untrusted data as the binding's initial value on the server.

Add the preset :preserveSemverRanges to your config if you don't want to pin your dependencies.

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Configuration

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This PR has been generated by Renovate Bot.