Svelte vulnerabilities

Svelte prior to version 5.55.7 contains a vulnerability where, when using spread syntax to render attributes from untrusted data, event handlers are included in the rendered HTML output. If an application spreads user-controlled data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. The vulnerability only triggers if the user's browser has JavaScript enabled and Svelte's hydration mechanism does not reach the vulnerable element before the event fires.

Svelte prior to version 5.55.7 is vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks.

Svelte framework versions 5.51.5 through 5.55.6 have a ReDoS vulnerability in <svelte:element this={tag}></svelte:element>. An internal regex can take exponential time to test.