CVE-2026-114061

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.

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.

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 <meta http-equiv="cache-control"> 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.

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This advisory has been withdrawn because it is a duplicate of GHSA-27mw-82g8-phjj.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.

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.

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.

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 <meta http-equiv="cache-control"> 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.

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.