CVE-2025-41082
📋 TL;DR
This vulnerability allows attackers to send malformed HTTP requests that cause desynchronization between frontend and backend servers in Altitude Communication Server. This can lead to request smuggling, cache poisoning, or security bypasses. Organizations using vulnerable versions of Altitude Communication Server are affected.
💻 Affected Systems
- Altitude Communication Server
⚠️ 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 bypass security controls, poison caches to serve malicious content to users, or hide malicious requests from detection systems.
Likely Case
Request smuggling leading to cache poisoning or security bypass, potentially allowing unauthorized access or data exposure.
If Mitigated
Limited impact with proper network segmentation, WAF rules, and monitoring in place.
🎯 Exploit Status
Exploitation requires crafting specific HTTP request sequences but does not require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific patched version
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-altitude-communication-server
Restart Required: Yes
Instructions:
1. Review the vendor advisory. 2. Download and apply the latest patch from the vendor. 3. Restart the Altitude Communication Server service. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Disable HTTP Keep-Alive
allPrevents the vulnerability by disabling persistent connections that enable request smuggling.
Configure server to set 'Connection: close' header or disable Keep-Alive in server settings
Implement WAF Rules
allUse a Web Application Firewall to detect and block malformed HTTP requests with inconsistent Content-Length headers.
Add WAF rules to reject requests with CL.0 anomalies or multiple Content-Length headers
🧯 If You Can't Patch
- Segment the network to restrict access to the server from untrusted sources.
- Monitor logs for unusual HTTP request patterns and implement rate limiting.
🔍 How to Verify
Check if Vulnerable:
Check server version against vendor advisory; test with crafted HTTP requests to see if request desynchronization occurs.Check Version:
Check server documentation or administrative interface for version information; command varies by installation.Verify Fix Applied:
After patching, test with the same crafted requests to confirm no desynchronization; verify version matches patched release.📡 Detection & Monitoring
Log Indicators:
- Multiple HTTP requests with inconsistent Content-Length headers in logs
- Unusual request sequences or desynchronization errors
Network Indicators:
- Anomalous HTTP traffic patterns, especially with Keep-Alive connections
- Requests that bypass expected security controls
SIEM Query:
Example: search for HTTP requests with 'Content-Length: 0' or multiple Content-Length headers in web server logs.