CVE-2025-0869
📋 TL;DR
This vulnerability allows attackers to inject malicious scripts via the browserLang parameter in the login component of Cianet ONU GW24AC devices. The cross-site scripting (XSS) attack can be executed remotely, potentially compromising user sessions. All users of affected ONU GW24AC devices are at risk.
💻 Affected Systems
- Cianet ONU GW24AC
⚠️ 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 could steal administrator credentials, hijack user sessions, deface login pages, or redirect users to malicious sites, potentially leading to full device compromise.
Likely Case
Session hijacking or credential theft through malicious script execution when users access the login page with a crafted browserLang parameter.
If Mitigated
Limited impact with proper input validation and output encoding, though the vulnerability still exists in the codebase.
🎯 Exploit Status
Exploit has been publicly disclosed and requires minimal technical skill to execute via crafted HTTP requests.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
No official patch available. Monitor vendor website for firmware updates addressing CVE-2025-0869.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side validation to sanitize the browserLang parameter, allowing only expected language codes.
Output Encoding
allApply proper HTML encoding to the browserLang parameter before rendering it in the login page.
🧯 If You Can't Patch
- Isolate affected devices behind a web application firewall (WAF) with XSS protection rules enabled.
- Restrict network access to the login interface to trusted IP addresses only.
🔍 How to Verify
Check if Vulnerable:
Test by accessing the login page with a crafted browserLang parameter containing script tags (e.g., ?browserLang=<script>alert('test')</script>) and check if script executes.Check Version:
Check device firmware version via web interface or CLI; vulnerable if version is 20250127 or earlier.Verify Fix Applied:
Verify that script payloads in the browserLang parameter are properly sanitized or blocked and do not execute in the browser.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to login page with suspicious browserLang parameters containing script tags or encoded payloads.
Network Indicators:
- Unusual traffic patterns to login endpoints with long or malformed browserLang values.
SIEM Query:
source="web_logs" AND uri="/login" AND query_string CONTAINS "browserLang=" AND (query_string CONTAINS "<script>" OR query_string CONTAINS "javascript:")