CVE-2026-82259

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 44% of CVEs (scores of 2026-10-25)

CWE

CWE-502

Published

2026-08-28

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

Affected

• svelte:sveltekit

Packages (OSV)

References

• https://github.com/sveltejs/kit/security/advisories/GHSA-fpg4-jhqr-589c
• https://www.vulncheck.com/advisories/sveltekit-2.49.0-before-2.53.3-denial-of-service-via-form

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