GHSA-j62c-4x62-9r35
SvelteKit is vulnerable to denial of service and possible SSRF when using prerendering
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@sveltejs/kitnpm@sveltejs/adapter-nodenpmDescription
Summary
Versions of SvelteKit are vulnerable to a server side request forgery (SSRF) and denial of service (DoS) under certain conditions.
Details
Affected versions from 2.44.0 onwards are vulnerable to DoS if:
- your app has at least one prerendered route (
export const prerender = true)
Affected versions from 2.19.0 onwards are vulnerable to DoS and SSRF if:
- your app has at least one prerendered route (
export const prerender = true) - AND you are using
adapter-nodewithout a configuredORIGINenvironment variable, and you are not using a reverse proxy that implements Host header validation
Impact
The DoS causes the running server process to end.
The SSRF allows access to internal services that can be reached without authentication when fetched from SvelteKit's server runtime.
It is also possible to obtain an SXSS via cache poisoning, by forcing a potential CDN to cache an XSS returned by the attacker's server (the latter being able to specify the cache-control of their choice).
Credits
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @sveltejs/kit | ≥ 2.19.0&&< 2.49.5 | 2.49.5 |
| 📦npm | @sveltejs/adapter-node | ≥ 5.4.1&&< 5.5.1 | 5.5.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @sveltejs/kit. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @sveltejs/kit to 2.49.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j62c-4x62-9r35 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-j62c-4x62-9r35 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-j62c-4x62-9r35. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-j62c-4x62-9r35 in your dependencies?
O3 detects GHSA-j62c-4x62-9r35 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.