CVE-2025-62381 sveltekit-superforms Prototype Pollution in `parseFormData` function of `formData.js`
Prototype pollution in sveltekit-superforms allows attackers to inject properties into Object.prototype, causing denial of service or potential remote code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-62381?
CVE-2025-62381 is a high-severity vulnerability in ciscoheat sveltekit-superforms, published on 15 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-1321
Which versions are affected by CVE-2025-62381?
2 open source packages ship an affected version, including sveltekit-superforms.
| Package | Affected | Fixed in |
|---|---|---|
sveltekit-superforms npm | All versions | 2.27.4 |
sveltekit-superforms npm | All versions | 2.27.4 |
How do I fix CVE-2025-62381?
Upgrade sveltekit-superforms to 2.27.4 or later.
Is CVE-2025-62381 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62381 exists.
Sources
Also known as GHSA-hwmc-4c8j-xxj7.