CVE-2026-82257: SvelteKit before 2.69.1 Prototype Pollution via File Input

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-28 · updated 2026-10-08
Weakness: CWE-1321

Description

SvelteKit versions before 2.69.1 contain a prototype pollution vulnerability in remote form functions with file input fields that accept arbitrary user-controlled path names. Attackers can manipulate the deletion path to remove methods on the prototype, potentially disabling application functionality.

Affected products

sveltejs kit: before 2.69.1 — fixed in 2.69.1

How to fix

Upgrade to a fixed version: sveltejs kit 2.69.1. Check the vendor advisory for mitigations.

References

https://github.com/sveltejs/kit/security/advisories/GHSA-866w-xmhq-wj7x
https://www.vulncheck.com/advisories/sveltekit-before-2.69.1-prototype-pollution-via-file-input

Get alerted when CVE-2026-82257 or the next vulnerability affects your stack