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.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Svelte Devalue
PublishedJun 9, 2026
First seenJun 9, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Update
- svelte devalue5.8.1 or later
- devalue5.8.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| svelte devalue | 5.6.3 ≤ v < 5.8.1 | 5.8.1 |
| devaluenpm | 5.6.3 ≤ v < 5.8.1 | 5.8.1 |
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