Package Instance

Svelte affected by cross-site scripting via spread attributes in Svelte SSR
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.

Svelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent`
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.

Svelte SSR attribute spreading includes inherited properties from prototype chain
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.

Svelte SSR does not validate dynamic element tag names in `<svelte:element>`
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.