ghsa-6q87-84jw-cjhp
Vulnerability from github
Summary
Unsanitized search param names cause XSS vulnerability. You are affected if you iterate over all entries of event.url.searchParams inside a server load function. Attackers can exploit it by crafting a malicious URL and getting a user to click a link with said URL.
Details
SvelteKit tracks which parameters in event.url.searchParams are read inside server load functions. If the application iterates over the these parameters, the uses.search_params array included in the boot script (embedded in the server-rendered HTML) will have any search param name included in unsanitized form.
packages/kit/src/runtime/server/utils.js:150 has the stringify_uses(node) function which prints these out.
Reproduction
In a +page.server.js or +layout.server.js:
```js /* @type {import('@sveltejs/kit').Load} / export function load(event) { const values = {};
for (const key of event.url.searchParams.keys()) { values[key] = event.url.searchParams.get(key); } } ```
If a user visits the page in question via a link containing ?</script/><script>window.pwned%3D1</script/>, the </script> will be included verbatim in the payload, causing the embedded script to be executed.
It is not necessary to return the parameter value from load or render it in the page, only to read it (which causes it to be tracked as a dependency) while load is running.
Impact
Any application that iterates over all values in event.url.searchParams in a load function in +page.server.js or +layout.server.js (directly or indirectly) is vulnerable to XSS.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "@sveltejs/kit"
},
"ranges": [
{
"events": [
{
"introduced": "2.0.0"
},
{
"fixed": "2.20.6"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-32388"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2025-04-14T19:10:42Z",
"nvd_published_at": "2025-04-15T23:15:42Z",
"severity": "MODERATE"
},
"details": "### Summary\n\nUnsanitized search param names cause XSS vulnerability. You are affected if you iterate over all entries of `event.url.searchParams` inside a server `load` function. Attackers can exploit it by crafting a malicious URL and getting a user to click a link with said URL.\n\n### Details\n\nSvelteKit tracks which parameters in `event.url.searchParams` are read inside server `load` functions. If the application iterates over the these parameters, the `uses.search_params` array included in the boot script (embedded in the server-rendered HTML) will have any search param name included in unsanitized form.\n\n`packages/kit/src/runtime/server/utils.js:150` has the `stringify_uses(node)` function which prints these out.\n\n### Reproduction\n\nIn a `+page.server.js` or `+layout.server.js`:\n\n```js\n/** @type {import(\u0027@sveltejs/kit\u0027).Load} */\nexport function load(event) {\n const values = {};\n\n for (const key of event.url.searchParams.keys()) {\n values[key] = event.url.searchParams.get(key);\n }\n}\n```\n\nIf a user visits the page in question via a link containing `?\u003c/script/\u003e\u003cscript\u003ewindow.pwned%3D1\u003c/script/\u003e`, the `\u003c/script\u003e` will be included verbatim in the payload, causing the embedded script to be executed.\n\nIt is not necessary to return the parameter value from `load` or render it in the page, only to read it (which causes it to be tracked as a dependency) while `load` is running.\n\n### Impact\n\nAny application that iterates over all values in `event.url.searchParams` in a `load` function in `+page.server.js` or `+layout.server.js` (directly or indirectly) is vulnerable to XSS.",
"id": "GHSA-6q87-84jw-cjhp",
"modified": "2025-04-16T00:40:49Z",
"published": "2025-04-14T19:10:42Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/sveltejs/kit/security/advisories/GHSA-6q87-84jw-cjhp"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-32388"
},
{
"type": "WEB",
"url": "https://github.com/sveltejs/kit/commit/d3300c6a67908590266c363dba7b0835d9a194cf"
},
{
"type": "PACKAGE",
"url": "https://github.com/sveltejs/kit"
},
{
"type": "WEB",
"url": "https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%402.20.6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "@sveltejs/kit vulnerable to Cross-site Scripting via tracked search_params"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.