PatchSiren cyber security CVE debrief

CVE-2026-42573 sveltejs CVE debrief

CVE-2026-42573 is a MEDIUM severity vulnerability in Svelte, 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.

Vendor: sveltejs
Product: svelte
CVSS: MEDIUM 5.3
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-09
Original CVE updated: 2026-06-11
Advisory published: 2026-06-09
Advisory updated: 2026-06-11

Who should care

Users of Svelte framework versions prior to 5.55.7 should update to the patched version to prevent potential XSS attacks.

Technical summary

The vulnerability, with a CVSS score of 5.3, involves DOM clobbering of Svelte's internal framework state on elements. This could potentially lead to Cross-Site Scripting (XSS) attacks.

Defensive priority

MEDIUM

Recommended defensive actions

Update Svelte to version 5.55.7 or later.

Evidence notes

Evidence from the National Vulnerability Database (NVD) and Svelte's official GitHub repository confirm the vulnerability and the patch.

Official resources

CVE-2026-42573 CVE record
CVE.org
CVE-2026-42573 NVD detail
NVD
Source item URL
nvd_modified
Mitigation or vendor reference
[email protected] - Product, Release Notes
Mitigation or vendor reference
[email protected] - Vendor Advisory

CVE-2026-42573 was published on 2026-06-09T17:17:07.400Z and modified on 2026-06-11T18:46:50.667Z.