CVE-2026-66062
MEDIUMSvelteKit: ReDoS (O(n^2)) in content negotiation — unauthenticated DoS via the Accept header
Title source: cnaDescription
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/sveltejs/kit/security/advisories/GHSA-29g2-3rmr-qm68
X_Refsource_Misc x_refsource_misc
https://github.com/sveltejs/kit/commit/82712fc02c24b1dcf5b25d7a52129cd8455f04f5
X_Refsource_Misc x_refsource_misc
https://github.com/sveltejs/kit/releases/tag/@sveltejs/kit@2.70.2
Scores
CVSS v3
5.3
EPSS
0.0029
EPSS Percentile
21.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-1333
Status
published
Products (2)
sveltejs/kit
0 - 2.70.2npm
sveltejs/kit
< 2.70.2
Published
Aug 07, 2026
Tracked Since
Aug 07, 2026