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CVE-2026-42570

Svelte devalue: DoS via sparse array deserialization

Published: Jun 9, 2026Updated: Jun 11, 2026 Sources: CVE List NVDCWE-770
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.3%
Top 73.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-770

Affected Products

devaluesveltejs
Library
OSS Libraries / web-framework
devaluesvelte
Library
OSS Libraries / web-framework
sveltejsoss-projectOSS Libraries
svelteoss-projectOSS Librariesaka kit, sveltekit

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/sveltejs/devalue/security/advisories/GHSA-77vg-94rm-hx3p
github.com
https://github.com/sveltejs/devalue/commit/206ca6712fbc380a4571c59de9ab04b91110792d
github.com
https://github.com/sveltejs/devalue/releases/tag/v5.8.1
github.com

Timeline

Published
Jun 9, 2026
Last Updated
Jun 11, 2026

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