CVE-2026-82257 SvelteKit before 2.69.1 Prototype Pollution via File Input
Attackers can cause denial of service in SvelteKit applications by exploiting prototype pollution in remote form file inputs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-82257?
CVE-2026-82257 is a medium-severity vulnerability in sveltejs kit, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-1321
Which versions are affected by CVE-2026-82257?
2 open source packages ship an affected version, including @sveltejs/kit. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@sveltejs/kit npm | All versions | 2.69.1 |
@sveltejs/kit npm | All versions | 2.69.1 |
Products include Svelte Sveltekit.
How do I fix CVE-2026-82257?
Upgrade @sveltejs/kit to 2.69.1 or later.
Is CVE-2026-82257 being exploited?
There is no known exploitation of CVE-2026-82257 in the wild and no public exploit code.
Other vulnerabilities in sveltejs kit
- CVE-2023-29008 SvelteKit framework has Insufficient CSRF protection for CORS requests
- CVE-2023-29003 SvelteKit has Insufficient Cross-Site Request Forgery Protection
- CVE-2026-82259 SvelteKit 2.49.0 before 2.53.3 Denial of Service via form
- CVE-2026-82260 SvelteKit before 2.52.2 Memory Exhaustion via Remote Form Deserialization
- CVE-2026-82261 SvelteKit before 2.52.2 CPU Exhaustion via Remote Form Deserialization
Sources
Also known as GHSA-6mgf-42wv-8j7p, GHSA-866w-xmhq-wj7x.