CVE-2026-66062

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.70.2, the content negotiation header parser used by SvelteKit's request handling for headers such as Accept uses a regular expression vulnerable to quadratic backtracking, so a maliciously...

SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header

Impact SvelteKit is vulnerable to remote CPU-exhaustion DoS attacks via specifically-crafted Accept headers. The impact is mitigated by default header length limits on most platforms, but in the case of raised or absent limits a denial of service is possible. Patches The vulnerability is patched ...

CVE-2026-66062 SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.70.2, the content negotiation header parser used by SvelteKit's request handling for headers such as Accept uses a regular expression vulnerable to quadratic backtracking, so a maliciously...

CVE-2026-66062

SvelteKit before 2.70.2 uses a content-negotiation header parser that employs a regular expression vulnerable to quadratic backtracking. A crafted Accept header can cause excessive CPU use, leading to degraded performance or denial of service. The issue is fixed in 2.70.2. No exploitation details...

CVE-2026-66062 SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.70.2, the content negotiation header parser used by SvelteKit's request handling for headers such as Accept uses a regular expression vulnerable to quadratic backtracking, so a maliciously...

EUVD-2026-54557

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.70.2, the content negotiation header parser used by SvelteKit's request handling for headers such as Accept uses a regular expression vulnerable to quadratic backtracking, so a maliciously...

GHSA-866W-XMHQ-WJ7X SvelteKit: Prototype pollution in file input deletion path in remote-function forms

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...

GHSA-HGV7-V322-MMGR @sveltejs/kit: `query.batch` cross-talk

query.batch could, under very rare and specific timings, cause concurrent requests from different users to merge and resolve under single request context, enabling cross-user data disclosure...

PT-2026-33834

I found a stored XSS vulnerability in @LenisSmooth that affected 800,000+ weekly npm downloads across Next.js, Nuxt, and SvelteKit deployments. Fixed in v1.3.22. Assigned CVE-2026-41251. If you're using Lenis — please update now. BugBounty XSS WebSecurity OpenSource CVE https://t.co/tsfYQ33N3I...

CVE-2026-40074

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This...

CVE-2026-40073

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, under certain circumstances, requests could bypass the BODYSIZELIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers...

EUVD-2026-21504

@sveltejs/kit: Unvalidated redirect in handle hook causes Denial-of-Service...

@sveltejs/kit: Unvalidated redirect in handle hook causes Denial-of-Service

redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This could result in DoS on some platforms, especially if the location passed to redirect contains unsanitized user input...

Improper Handling of Exceptional Conditions

Overview @sveltejs/kit is a SvelteKit framework and CLI Affected versions of this package are vulnerable to Improper Handling of Exceptional Conditions in the redirect function in the handle server hook when the location parameter contains characters invalid in an HTTP header. An attacker can cau...

EUVD-2026-21502

@sveltejs/adapter-node has a BODYSIZELIMIT bypass...

GHSA-2CRG-3P73-43XP @sveltejs/adapter-node has a BODY_SIZE_LIMIT bypass

Under certain circumstances, requests could bypass the BODYSIZELIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers of the application stack, so limits enforced in the WAF, gateway, or at the platform level are unaffected...

Allocation of Resources Without Limits or Throttling

Overview @sveltejs/kit is a SvelteKit framework and CLI Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the request processing. An attacker can send requests that exceed BODYSIZELIMIT restriction to applications running with adapter-node...

CVE-2026-40073

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, under certain circumstances, requests could bypass the BODYSIZELIMIT on SvelteKit applications running with adapter-node. This bypass does not affect body size limits at other layers...

CVE-2026-40074

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This...

CVE-2026-40074 SvelteKit's invalidated redirect in handle hook causes Denial-of-Service

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Prior to 2.57.1, redirect, when called from inside the handle server hook with a location parameter containing characters that are invalid in a HTTP header, will cause an unhandled TypeError. This...