ciscoheat sveltekit-superforms up to 2.27.3 formData.js parseFormData prototype pollution

Summaryinfo

A vulnerability marked as problematic has been reported in ciscoheat sveltekit-superforms up to 2.27.3. This issue affects the function parseFormData of the file formData.js. This manipulation causes prototype pollution. This vulnerability is tracked as CVE-2025-62381. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in ciscoheat sveltekit-superforms up to 2.27.3. Affected by this vulnerability is the function parseFormData of the file formData.js. The manipulation with an unknown input leads to a prototype pollution vulnerability. The CWE definition for the vulnerability is CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

sveltekit-superforms makes SvelteKit forms a pleasure to use. 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. This vulnerability is fixed in 2.27.4.

The advisory is shared at github.com. This vulnerability is known as CVE-2025-62381 since 10/10/2025. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059 for this issue.

Upgrading to version 2.27.4 eliminates this vulnerability.

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Productinfo

Vendor

• ciscoheat

Name

• sveltekit-superforms

Version

• 2.27.0
• 2.27.1
• 2.27.2
• 2.27.3

Website

• Product: https://github.com/ciscoheat/sveltekit-superforms/

CPE 2.3info

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CPE 2.2info

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