Memory Consumption Issue in Svelte devalue JavaScript Library
CVE-2026-42570

7.5HIGH

Key Information:

Vendor

Sveltejs

Status
Devalue
Vendor
CVE Published:
9 June 2026

What is CVE-2026-42570?

The Svelte devalue library is susceptible to a memory consumption issue caused by its 'devalue.parse' function, which improperly handles sparse arrays. This can trigger excessive memory allocation due to behavioral quirks in various JavaScript engines, leading to significant resource strain. Users should update to version 5.8.1 or later, where the issue has been resolved, to protect against potential performance degradation.

Affected Version(s)

devalue >= 5.6.3, < 5.8.1

References

https://github.com/sveltejs/devalue/security/advisories/G...
x_refsource_CONFIRM
https://github.com/sveltejs/devalue/commit/206ca6712fbc38...
x_refsource_MISC
https://github.com/sveltejs/devalue/releases/tag/v5.8.1
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.