CVE-2026-66062
SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
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 crafted header value can cause excessive CPU consumption and degrade or deny service. Version 2.70.2 fixes the issue.
| CWE | CWE-1333 |
| Vendor | sveltejs |
| Product | kit |
| Published | Aug 7, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
sveltejs / kit
< 2.70.2