CVE-2026-42567

HIGH

Svelte: ReDoS in `<svelte:element>` Tag Validation

Title source: cna
STIX 2.1

Description

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.

References (2)

Core 2
Core References

Scores

CVSS v3 7.5
EPSS 0.0042
EPSS Percentile 33.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-1333
Status published
Products (3)
npm/svelte 5.51.5 - 5.55.7npm
svelte/svelte 5.51.5 - 5.55.7
sveltejs/svelte >= 5.51.5, < 5.55.7
Published Jun 09, 2026
Tracked Since Jun 09, 2026