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Deserialization expansion in unvalidated SvelteKit `form` remote function leads to denial of service (experimental only)

Low
elliott-with-the-longest-name-on-github published GHSA-fpg4-jhqr-589c Feb 26, 2026

Package

npm @sveltejs/kit (npm)

Affected versions

>=2.49.0 <=2.53.2

Patched versions

2.53.3

Description

Some relatively small inputs can cause very large files arrays in form handlers. If the SvelteKit application code doesn't check files.length or individual files' sizes and performs expensive processing with them, it can result in denial of service.

Only users with experimental.remoteFunctions: true who are using the form function and are processing the files array without validation are vulnerable.

Severity

Low

CVE ID

No known CVE

Weaknesses

No CWEs

Credits