CVE-2025-32388
📋 TL;DR
This CVE describes a cross-site scripting (XSS) vulnerability in SvelteKit where unsanitized search parameter names can be exploited when iterating over all entries of event.url.searchParams in server load functions. Attackers can craft malicious URLs that, when clicked by users, execute arbitrary JavaScript in the victim's browser context. Only applications using affected SvelteKit versions with server load functions that iterate over all search parameters are vulnerable.
💻 Affected Systems
- SvelteKit
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers can execute arbitrary JavaScript in victim's browser, potentially stealing session cookies, performing actions as the user, or redirecting to malicious sites.
Likely Case
Attackers craft phishing links that execute JavaScript payloads when clicked, potentially stealing user data or session tokens.
If Mitigated
With proper input sanitization and Content Security Policy (CSP) headers, impact is limited to script execution within CSP constraints.
🎯 Exploit Status
Exploitation requires user interaction (clicking malicious link) but is straightforward once the vulnerable code pattern is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.20.6
Vendor Advisory: https://github.com/sveltejs/kit/security/advisories/GHSA-6q87-84jw-cjhp
Restart Required: Yes
Instructions:
1. Update SvelteKit to version 2.20.6 or later using npm: 'npm update @sveltejs/kit' 2. Restart your application server 3. Verify the update with 'npm list @sveltejs/kit'
🔧 Temporary Workarounds
Sanitize search parameter names manually
allManually sanitize search parameter names before processing in server load functions
// Example: Sanitize parameter names before iteration
const sanitizedParams = new URLSearchParams();
for (const [key, value] of event.url.searchParams) {
const sanitizedKey = key.replace(/[<>"']/g, ''); // Basic sanitization
sanitizedParams.set(sanitizedKey, value);
}
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to limit script execution
- Review and modify server load functions to avoid iterating over all search parameter entries
🔍 How to Verify
Check if Vulnerable:
Check if your SvelteKit version is below 2.20.6 and review server load functions for iteration over event.url.searchParams entriesCheck Version:
npm list @sveltejs/kitVerify Fix Applied:
Verify SvelteKit version is 2.20.6 or higher and test that search parameter iteration no longer allows XSS📡 Detection & Monitoring
Log Indicators:
- Unusual search parameter names containing script tags or JavaScript in URL logs
- Multiple failed requests with malformed parameter names
Network Indicators:
- HTTP requests with search parameters containing script tags or JavaScript code
SIEM Query:
url:*search* AND (url:*<script* OR url:*javascript:* OR url:*onerror=*)