CVE-2025-3268
📋 TL;DR
This vulnerability allows remote attackers to bypass authentication mechanisms in TinyWebServer by manipulating the m_url_real argument in http/http_conn.cpp. Attackers can potentially access restricted resources without proper credentials. All users running TinyWebServer version 1.0 or earlier are affected.
💻 Affected Systems
- qinguoyi TinyWebServer
📦 What is this software?
Tinywebserver by Qinguoyi
⚠️ Risk & Real-World Impact
Worst Case
Complete authentication bypass allowing unauthorized access to all protected resources, potentially leading to data theft, privilege escalation, or server compromise.
Likely Case
Unauthorized access to restricted files or administrative interfaces, potentially exposing sensitive configuration data or allowing unauthorized operations.
If Mitigated
Limited impact with proper network segmentation and additional authentication layers preventing access to critical systems.
🎯 Exploit Status
Public exploit details are available, making this easy to weaponize. The vulnerability requires no authentication to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch is available. Consider upgrading to a forked/maintained version or implementing workarounds.
🔧 Temporary Workarounds
Implement reverse proxy with authentication
allPlace TinyWebServer behind a reverse proxy (nginx, Apache) that handles authentication before requests reach the vulnerable server.
Network access restrictions
linuxRestrict network access to TinyWebServer using firewall rules to only allow trusted IP addresses.
iptables -A INPUT -p tcp --dport [TinyWebServer_port] -s [trusted_ip] -j ACCEPT
iptables -A INPUT -p tcp --dport [TinyWebServer_port] -j DROP
🧯 If You Can't Patch
- Isolate TinyWebServer in a segmented network zone with strict access controls
- Implement application-level authentication wrapper or replace with alternative web server software
🔍 How to Verify
Check if Vulnerable:
Check if running TinyWebServer version 1.0 or earlier. Review source code for vulnerable http_conn.cpp file with improper m_url_real authentication.Check Version:
Check server startup logs or configuration files for version information. No standard version command exists.Verify Fix Applied:
Test authentication bypass attempts against protected resources. Successful authentication should be required for all restricted endpoints.📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to protected URLs without authentication logs
- Failed authentication attempts followed by successful access to restricted resources
Network Indicators:
- HTTP requests manipulating URL parameters to bypass authentication
- Direct access to admin/protected endpoints without prior login
SIEM Query:
source="TinyWebServer" AND (url="*admin*" OR url="*protected*" OR url="*restricted*") AND NOT auth_success="true"🔗 References
- https://magnificent-dill-351.notion.site/Improper-Authentication-in-TinyWebServer-1-0-1c9c693918ed80cfa0f5db1a1d03c5e7
- https://vuldb.com/?ctiid.303340
- https://vuldb.com/?id.303340
- https://vuldb.com/?submit.549229
- https://magnificent-dill-351.notion.site/Improper-Authentication-in-TinyWebServer-1-0-1c9c693918ed80cfa0f5db1a1d03c5e7
