Vulnerability · Published Aug 28, 2026 · Assigned by VulnCheck
CVE-2026-82257SvelteKit before 2.69.1 Prototype Pollution via File Input
Medium 4.3
In plain English
A medium-severity prototype pollution in kit from sveltejs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.4%top 70.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @sveltejs/kit | 2.69.1 | GHSA-866w-xmhq-wj7x |
Affected products (as reported)
Weakness: CWE-1321 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
References
- GitHub Security Advisory (GHSA-866w-xmhq-wj7x) vendor-advisory
- VulnCheck Advisory: SvelteKit before 2.69.1 Prototype Pollution via File Input third-party-advisory