CVE-2024-53262 — @sveltejs/kit
Fix: sveltejs/kit@134e363CVE-2024-53262 is a Cross-site Scripting (XSS) vulnerability in @sveltejs/kit. A fix is available for @sveltejs/kit — see the affected versions and patch details below.
Unescaped error message included on error page in SvelteKit
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-53262.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@sveltejs/kitnpmDescription
Summary
The static error.html template for errors contains placeholders that are replaced without escaping the content first.
Details
From https://kit.svelte.dev/docs/errors:
error.html is the page that is rendered when everything else fails. It can contain the following placeholders: %sveltekit.status% — the HTTP status %sveltekit.error.message% — the error message
This leads to possible injection if an app explicitly creates an error with a message that contains user controlled content that ends up being something like this inside a server handle function:
error(500, '<script>alert("boom")</script>');
Uncaught errors cannot be exploited like this, as they always render the message "Internal error".
Escaping the message string in the function that creates the html output can be done to improve safety for applications that are using custom errors on the server.
PoC
None provided
Impact
Only applications where user provided input is used in the Error message will be vulnerable, so the vast majority of applications will not be vulnerable
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @sveltejs/kit | all versions | 2.8.3npm install @sveltejs/kit@2.8.3 |
Affected Products
sveltekitsvelteDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @sveltejs/kit to 2.8.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-53262 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2024-53262 in your dependencies?
Find it across npm, including transitive dependencies.