CVE-2025-22871
📋 TL;DR
This vulnerability in Go's net/http package allows HTTP request smuggling when servers incorrectly accept bare line feed characters as chunked transfer encoding terminators. It affects Go applications using net/http as a server, particularly when deployed behind proxies or load balancers with different HTTP parsing behavior.
💻 Affected Systems
- Go programming language
⚠️ 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 smuggle malicious requests, bypass security controls, poison caches, or perform session hijacking and credential theft.
Likely Case
Request smuggling leading to cache poisoning, security control bypass, or unauthorized access to backend systems.
If Mitigated
Limited impact if proper WAFs, request validation, and updated proxy servers are in place.
🎯 Exploit Status
Exploitation requires specific proxy/server configurations and knowledge of target architecture.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Go 1.22.11, Go 1.23.3
Vendor Advisory: https://groups.google.com/g/golang-announce/c/Y2uBTVKjBQk
Restart Required: Yes
Instructions:
1. Update Go to version 1.22.11 or 1.23.3. 2. Recompile and redeploy affected applications. 3. Restart all services using the patched Go runtime.
🔧 Temporary Workarounds
Use alternative HTTP server
allTemporarily switch to a different HTTP server implementation not using net/http package
Deploy WAF with HTTP normalization
allConfigure Web Application Firewall to normalize HTTP requests and reject malformed chunked encoding
🧯 If You Can't Patch
- Deploy reverse proxies that normalize HTTP requests before forwarding to Go applications
- Implement request validation middleware to detect and reject malformed chunked transfer encoding
🔍 How to Verify
Check if Vulnerable:
Check Go version with 'go version'. If version is between 1.22.0-1.22.10 or 1.23.0-1.23.2 and application uses net/http server, it's vulnerable.Check Version:
go versionVerify Fix Applied:
Verify Go version is 1.22.11 or 1.23.3+ with 'go version'. Test with HTTP requests containing bare LF in chunked encoding to confirm rejection.📡 Detection & Monitoring
Log Indicators:
- HTTP 400 errors for malformed requests
- Unusual request patterns in access logs
- Requests with abnormal Content-Length or Transfer-Encoding headers
Network Indicators:
- HTTP requests with bare LF characters in chunked encoding
- Mismatched request/response patterns between proxy and backend
SIEM Query:
source="web_logs" AND (http_status=400 AND (message="*chunk*" OR message="*transfer-encoding*"))