Summary
SvelteKit: Prototype pollution in file input deletion path in remote-function forms
Advisory details
If you use remote form functions, have an input field of type file, and accept arbitrary user-controlled path names for the field, then you are vulnerable to a prototype pollution attack where the attacker can remove e.g. methods on the prototype.
References
- https://github.com/advisories/GHSA-866w-xmhq-wj7x
- https://github.com/sveltejs/kit/security/advisories/GHSA-866w-xmhq-wj7x
- https://github.com/sveltejs/kit/pull/16218
- https://github.com/sveltejs/kit/commit/df32f6fe86cdd0b68b650e3e4631e5896453dcd3
- https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.69.1
- https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@3.0.0-next.7
Related vulnerabilities
All Supply chain →- HIGHCVE-2026-63376
toml-node: Prototype Pollution Leads to `Object.prototype` Corruption via `__proto__` Key-Path Desynchronization
- HIGHCVE-2026-82404
TOON: Prototype pollution when decoding untrusted TOON input
- HIGHCVE-2026-71553
ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS
- MEDIUMGHSA-cp6q-959q-f8rh
Tiptap: mergeAttributes() turns an own __proto__ key into inherited executable DOM attributes
- MEDIUMCVE-2026-81887
Livewire DOM-based cross-site scripting during client-side state handling
- HIGHCVE-2026-73088
Browserslist: Uncaught crash / prototype write via untrusted browserslist-stats.json custom stats (normalizeStats)