CVE-2026-82259: Svelte Sveltekit

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

SvelteKit versions from 2.49.0 through 2.53.2 (fixed in 2.53.3) contain a deserialization expansion issue in the experimental form remote function. When an application enables experimental.remoteFunctions and uses the form function to process the files array without validating files.length or individual file sizes, an attacker can submit relatively small inputs that expand into very large file arrays, leading to expensive processing and denial of service.

Affected products

• Svelte Sveltekit: from 2.49.0, before 2.53.3 (fixed in 2.53.3)

Published 2026-08-28. Last modified 2026-10-08.