---
id: "GHSA-85pr-xr59-r75h"
kind: "vulnerability"
aliases: ["GHSA-85pr-xr59-r75h"]
title: "Duplicate Advisory: SvelteKit before 3.0.0 XSS via Cache-Control Header in Prerendered Pages"
severity: "medium"
cvss: 4.7
epss: null
exploited: false
status: "withdrawn"
category: "package"
products: [{"name": "@sveltejs/kit", "fixed": [], "affected": "< 3.0.0", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["cwe-79", "npm", "package", "prerendered-pages", "sveltekit"]
not_affected_if: ["kit-3.0.0-or-later", "no-prerendering", "no-untrusted-cache-header-input"]
published_at: "2026-10-21T03:32:18+00:00"
first_seen_at: "2026-10-23T20:45:22+00:00"
updated_at: "2026-10-23T20:46:23+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-85pr-xr59-r75h", "first_seen_at": "2026-10-23T20:45:22+00:00"}]
---

# Duplicate Advisory: SvelteKit before 3.0.0 XSS via Cache-Control Header in Prerendered Pages

This advisory is a withdrawn duplicate of GHSA-27mw-82g8-phjj, which covers the same SvelteKit issue. The original text says a Cache-Control header value set via setHeaders is inserted unescaped into a meta tag in prerendered pages, letting an attacker who controls that value run JavaScript in visitors' browsers.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:@sveltejs/kit affected < 3.0.0 fixed ?

## How to check

Run npm ls @sveltejs/kit to see the installed version and check whether you use prerendering with setHeaders.

## Fix

Upgrade @sveltejs/kit to 3.0.0 or later, per the original advisory GHSA-27mw-82g8-phjj.

## Timeline

- 2026-10-23T20:45:22+00:00 ghsa https://github.com/advisories/GHSA-85pr-xr59-r75h

## From the sources

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-27mw-82g8-phjj. This link is maintained to preserve external references.

## Original Description
SvelteKit (@sveltejs/kit) before 3.0.0 contains a cross-site scripting vulnerability in prerendered pages because a cache-control header value set via setHeaders is inserted without escaping into a <meta http-equiv="cache-control"> tag. An attacker who can influence that untrusted value at prerender time can break out of the content attribute and inject HTML or JavaScript that executes when users visit the page.

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