CVE-2025-57783
📋 TL;DR
An HTTP request smuggling vulnerability in Hiawatha webserver version 11.7 allows unauthenticated attackers to bypass security controls and access restricted resources. This affects all systems running the vulnerable version of Hiawatha webserver. Attackers can manipulate HTTP headers to smuggle requests that appear to belong to legitimate users.
💻 Affected Systems
- Hiawatha webserver
📦 What is this software?
Hiawatha by Hiawatha Webserver
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain unauthorized access to sensitive data, administrative interfaces, or backend systems protected by the webserver, potentially leading to data theft or further system compromise.
Likely Case
Attackers bypass authentication or authorization controls to access restricted web resources, directories, or applications hosted on the vulnerable server.
If Mitigated
With proper network segmentation and additional authentication layers, impact is limited to the specific Hiawatha instance without lateral movement.
🎯 Exploit Status
Exploitation requires crafting malicious HTTP requests with improper headers. No public exploit code has been identified yet.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 11.8 or later
Vendor Advisory: https://www.hiawatha-webserver.org/news
Restart Required: Yes
Instructions:
1. Download Hiawatha version 11.8 or later from the official website. 2. Stop the Hiawatha service. 3. Replace the existing Hiawatha binary with the new version. 4. Restart the Hiawatha service.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allConfigure WAF rules to detect and block HTTP request smuggling attempts by inspecting header anomalies.
Reverse Proxy Configuration
linuxPlace a reverse proxy (like nginx or Apache) in front of Hiawatha with strict HTTP header validation.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the vulnerable Hiawatha server from sensitive systems.
- Add additional authentication layers (like application-level auth) for accessing restricted resources.
🔍 How to Verify
Check if Vulnerable:
Check Hiawatha version using 'hiawatha -v' command. If output shows version 11.7, the system is vulnerable.Check Version:
hiawatha -vVerify Fix Applied:
After patching, run 'hiawatha -v' to confirm version is 11.8 or later, then test with HTTP request smuggling test tools.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP request patterns with malformed headers
- Multiple requests from single connections with inconsistent headers
- Access to restricted URLs without proper authentication logs
Network Indicators:
- HTTP requests with duplicate or malformed headers like Content-Length, Transfer-Encoding
- Requests that appear to be 'smuggled' within other requests
SIEM Query:
source="hiawatha" AND (http_header="Transfer-Encoding" OR http_header="Content-Length") AND status=200 AND uri="/restricted/*"