{"cve":"CVE-2026-66062","nvd":{"published":"2026-08-07T17:17:06.340","modified":"2026-10-24T16:10:00.153","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-1333"],"references":["https://github.com/sveltejs/kit/commit/82712fc02c24b1dcf5b25d7a52129cd8455f04f5","https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.70.2","https://github.com/sveltejs/kit/security/advisories/GHSA-29g2-3rmr-qm68"],"products":[],"source":"nvd","synced_at":"2026-10-24T16:53:34.184483516+00:00"},"epss":{"cve":"CVE-2026-66062","score":0.00507,"percentile":0.42953,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-29g2-3rmr-qm68","url":"https://osv.dev/vulnerability/GHSA-29g2-3rmr-qm68","summary":"SvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header","modified":"2026-08-07T17:10:58.809703Z","packages":[{"ecosystem":"npm","name":"@sveltejs/kit","purl":"pkg:npm/%40sveltejs/kit","ranges":["<2.70.2"],"fixed":["2.70.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}