CVE-2026-42570

high

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.

References

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42570.json

https://github.com/sveltejs/devalue/security/advisories/GHSA-77vg-94rm-hx3p

https://github.com/sveltejs/devalue/releases/tag/v5.8.1

https://github.com/sveltejs/devalue/commit/206ca6712fbc380a4571c59de9ab04b91110792d

https://bugzilla.redhat.com/show_bug.cgi?id=2487050

https://access.redhat.com/security/cve/CVE-2026-42570

Details

Source: Mitre, NVD

Published: 2026-06-09

Updated: 2026-06-30

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

EPSS

EPSS: 0.00038