CVE-2025-62381: `sveltekit-superforms` has Prototype Pollution in `parseFormData` function of `formData.js`

October 15, 2025

sveltekit-superforms v2.27.3 and prior are susceptible to a prototype pollution vulnerability within the parseFormData function of formData.js. An attacker can inject string and array properties into Object.prototype, leading to denial of service, type confusion, and potential remote code execution in downstream applications that rely on polluted objects.

References

github.com/advisories/GHSA-hwmc-4c8j-xxj7
github.com/ciscoheat/sveltekit-superforms
github.com/ciscoheat/sveltekit-superforms/commit/4a1310dd1a94176bb22036662c530dad48059ca4
github.com/ciscoheat/sveltekit-superforms/security/advisories/GHSA-hwmc-4c8j-xxj7
nvd.nist.gov/vuln/detail/CVE-2025-62381

Code Behaviors & Features

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