What’s Vulnerable › Vulnerabilities
CVE-2026-30226: devalue has prototype pollution in devalue.parse and devalue.unflatten
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-03-11 · updated 2026-06-17
- Weakness: CWE-1321
Description
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.
Affected products
- sveltejs devalue: before 5.6.4 — fixed in 5.6.4
How to fix
Upgrade to a fixed version: sveltejs devalue 5.6.4. Check the vendor advisory for mitigations.
References
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