GitHub Advisoryadvisory · npm

GHSA-27mw-82g8-phjj SvelteKit : XSS via untrusted cache-control header in prerendered page

LOW Published 2026-10-23 Modified 2026-10-23 Official page ↗
Aliases
CVE-2026-114061
Ecosystem
npm
Packages
@sveltejs/kit
Severity
Low
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N
Weaknesses
CWE-79
Reviewed
2026-10-23

Affected packages

• npm @sveltejs/kit: < 3.0.0 → fixed in 3.0.0

Description

Impact Applications that prerender pages and use `setHeaders` to set a `cache-control` header from an untrusted source are vulnerable to cross-site scripting (XSS). SvelteKit inserts the header value into a `` tag without escaping it. An attacker who can influence this value at prerender time can break out of the `content` attribute and inject HTML or JavaScript into the generated page. The injected code can then execute when users visit the page. Patches The fix escapes the header value before inserting it into the generated HTML. Upgrade to `@sveltejs/kit` version 3.0.0 or later. Workarounds Avoid forwarding untrusted `cache-control` header values with `setHeaders` on prerendered pages. Use a fixed, trusted cache policy instead.

Related

Alias · CVE (1)

  • CVE-2026-114061 SvelteKit (@sveltejs/kit) before 3.0.0 contains a cross-site scripting vulnerability in prerendered pages because a cache-control header… vulnerability

Weakness · CWE (1)

  • CWE-79 Improper Neutralization of Input During Web Page Generation weakness

References