# 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.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Jun 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-rcqx-6q8c-2c42

## 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 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-42573?

2 open source packages ship an affected version, including svelte. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `svelte` | npm | All versions | 5.55.7 |
| `svelte` | npm | All versions | 5.55.7 |

Products: Svelte Svelte.

## How do I fix CVE-2026-42573?

Upgrade svelte to 5.55.7 or later.

## 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](https://insights.sbomify.com/CVE-2021-29261/): Code injection in n/a (high 7.8)
- [CVE-2026-42567](https://insights.sbomify.com/CVE-2026-42567/): Svelte: ReDoS in `<svelte:element>` Tag Validation (medium 5.9)
- [CVE-2024-45047](https://insights.sbomify.com/CVE-2024-45047/): Potential mXSS vulnerability due to improper HTML escaping in svelte (medium 5.4)
- [CVE-2022-25875](https://insights.sbomify.com/CVE-2022-25875/): Cross-site Scripting (XSS) (medium 5.4)
- [CVE-2026-27901](https://insights.sbomify.com/CVE-2026-27901/): Svelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent` (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42573 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-42573 in the wild and no public exploit code.

Affected packages and fixed versions:
- svelte (npm): affected all versions; fixed in 5.55.7
- svelte (npm): affected all versions; fixed in 5.55.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42573/ (Markdown: https://insights.sbomify.com/CVE-2026-42573/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42573
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42573
- OSV: https://osv.dev/vulnerability/CVE-2026-42573

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42573/
Summaries are generated and may contain mistakes; the official description above is the record.