CVE-2023-29003 SvelteKit has Insufficient Cross-Site Request Forgery Protection
Attackers can bypass CSRF protection in SvelteKit by manipulating Content-Type headers, potentially executing unauthorized actions in victim sessions.
- 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
- Available
What is CVE-2023-29003?
CVE-2023-29003 is a high-severity vulnerability in sveltejs kit, published on 4 Apr 2023. 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 is a web development framework. The SvelteKit framework offers developers an option to create simple REST APIs. This is done by defining a `+server.js` file, containing endpoint handlers for different HTTP methods.
SvelteKit provides out-of-the-box cross-site request forgery (CSRF) protection to its users. While the implementation does a sufficient job in mitigating common CSRF attacks, prior to version 1.15.1, the protection can be bypassed by simply specifying a different `Content-Type` header value.
If abused, this issue will allow malicious requests to be submitted from third-party domains, which can allow execution of operations within the context of the victim's session, and in extreme scenarios can lead to unauthorized access to users’ accounts.
SvelteKit 1.15.1 updates the `is_form_content_type` function call in the CSRF protection logic to include `text/plain`. As additional hardening of the CSRF protection mechanism against potential method overrides, SvelteKit 1.15.1 is now performing validation on `PUT`, `PATCH` and `DELETE` methods as well. This latter hardening is only needed to protect users who have put in some sort of `?_method= override` feature themselves in their `handle` hook, so that the request that resolve sees could be `PUT`/`PATCH`/`DELETE` when the browser issues a `POST` request.
Which versions are affected by CVE-2023-29003?
2 open source packages ship an affected version, including @sveltejs/kit. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@sveltejs/kit npm | All versions | 1.15.1 |
@sveltejs/kit npm | All versions | 1.15.1 |
Products include Svelte Sveltekit.
How do I fix CVE-2023-29003?
Upgrade @sveltejs/kit to 1.15.1 or later.
Is CVE-2023-29003 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-29003 exists.
Other vulnerabilities in sveltejs kit
- CVE-2023-29008 SvelteKit framework has Insufficient CSRF protection for CORS requests
- 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
- CVE-2026-82256 SvelteKit before 2.69.1 Denial of Service via Remote Form
Sources
Also known as GHSA-5p75-vc5g-8rv2.