CVE-2026-42573 Svelte: XSS via DOM Clobbering of Internal Framework State
Attackers can exploit DOM clobbering in Svelte to execute arbitrary scripts, requiring developers to upgrade the framework.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42573?
CVE-2026-42573 is a medium-severity cross-site scripting vulnerability in sveltejs svelte, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Svelte is a performance oriented web framework. Prior to version 5.55.7, Svelte was vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks. This issue has been patched in version 5.55.7.
Weakness: CWE-79
Which versions are affected by CVE-2026-42573?
2 open source packages ship an affected version, including svelte. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
svelte npm | All versions | 5.55.7 |
svelte npm | All versions | 5.55.7 |
Products include Svelte Svelte.
How do I fix CVE-2026-42573?
Upgrade svelte to 5.55.7 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-42573 being exploited?
There is no known exploitation of CVE-2026-42573 in the wild and no public exploit code.
Other vulnerabilities in sveltejs svelte
- CVE-2021-29261 Code injection in n/a
- CVE-2026-42567 Svelte: ReDoS in `<svelte:element>` Tag Validation
- CVE-2024-45047 Potential mXSS vulnerability due to improper HTML escaping in svelte
- CVE-2022-25875 Cross-site Scripting (XSS)
- CVE-2026-27901 Svelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent`
Sources
Also known as GHSA-rcqx-6q8c-2c42.