CVE-2026-42567 MEDIUM

CVE-2026-42567: Svelte: ReDoS in `<svelte:element>` Tag Validation

Vendor Sveltejs
Product svelte
Weakness CWE-1333
Published June 9, 2026
Last update June 9, 2026
View on NVD All CVEs

CVSS base score

5.9/10
Attack vector Network
Attack complexity High
Privileges required High
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in <svelte:element this={tag}></svelte:element>. This issue has been patched in version 5.55.7.

Key dates

02Disclosure timeline

June 9, 2026 CVE published
June 9, 2026 Record updated