CVE-2026-42570

HIGH

Svelte devalue: DoS via sparse array deserialization

Title source: cna
STIX 2.1

Description

Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate much more memory than was needed when deserializing sparse arrays, leading to excessive memory consumption. This issue has been patched in version 5.8.1.

Scores

CVSS v3 7.5
EPSS 0.0004
EPSS Percentile 12.5%
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 yes
Technical Impact partial

Details

CWE
CWE-770
Status published
Products (3)
npm/devalue 5.6.3 - 5.8.1npm
svelte/devalue 5.6.3 - 5.8.1
sveltejs/devalue >= 5.6.3, < 5.8.1
Published Jun 09, 2026
Tracked Since Jun 09, 2026