CVE-2023-26137
📋 TL;DR
CVE-2023-26137 is an HTTP response splitting vulnerability in the Drogon C++ web framework. Attackers can inject malicious content into HTTP responses by adding carriage return line feed characters to header values. All applications using untrusted user input in Drogon's addHeader or addCookie functions are affected.
💻 Affected Systems
- drogonframework/drogon
📦 What is this software?
Drogon by Drogon
⚠️ 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 inject malicious JavaScript, redirect users to phishing sites, steal session cookies, or perform cross-site scripting attacks against users.
Likely Case
Session hijacking, cross-site scripting attacks, or content injection leading to user compromise.
If Mitigated
Limited impact with proper input validation and output encoding in place.
🎯 Exploit Status
Exploitation requires attacker to control input to vulnerable header functions. Public proof-of-concept demonstrates the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Drogon GitHub repository for latest patched version
Vendor Advisory: https://github.com/drogonframework/drogon/security/advisories
Restart Required: Yes
Instructions:
1. Update Drogon to the latest patched version. 2. Rebuild your application. 3. Restart the application server.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation and sanitization for all user-supplied data used in HTTP headers
Header Value Filtering
allFilter out CRLF sequences (\r\n) from all user input before passing to addHeader or addCookie functions
🧯 If You Can't Patch
- Implement strict input validation to reject any header values containing CRLF sequences
- Use a web application firewall (WAF) to detect and block HTTP response splitting attempts
🔍 How to Verify
Check if Vulnerable:
Review code for use of addHeader or addCookie with untrusted user input without proper validationCheck Version:
Check Drogon version in your project configuration or build filesVerify Fix Applied:
Test that CRLF sequences in header values are properly sanitized or rejected📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP response headers
- Multiple Set-Cookie headers
- Malformed HTTP responses
Network Indicators:
- HTTP responses containing unexpected JavaScript or redirects
- Responses with multiple CRLF sequences in headers
SIEM Query:
http.response.headers contains "\r\n" OR http.response.headers contains "%0D%0A"