PatchSiren

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
2026-07-15
Advisory published
2026-06-09
Advisory updated
2026-07-15

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-42573 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-42573

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-42573 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-42573

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.