CVE-2025-54972
📋 TL;DR
This CRLF injection vulnerability in Fortinet FortiMail allows attackers to inject HTTP headers into server responses by tricking users into clicking malicious links. Affected systems include FortiMail versions 7.0 through 7.6.3, potentially enabling header manipulation attacks.
💻 Affected Systems
- Fortinet FortiMail
📦 What is this software?
Fortimail by Fortinet
Fortimail by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Attackers could inject malicious headers leading to cache poisoning, session fixation, or cross-site scripting if combined with other vulnerabilities.
Likely Case
Header injection allowing manipulation of HTTP responses, potentially enabling phishing or session hijacking attacks.
If Mitigated
Limited impact with proper input validation and user awareness training.
🎯 Exploit Status
Exploitation requires user interaction but no authentication. Attack complexity is low once malicious link is crafted.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FortiMail 7.6.4, 7.4.6, and later versions
Vendor Advisory: https://fortiguard.fortinet.com/psirt/FG-IR-25-634
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download appropriate patch from Fortinet support portal. 3. Apply patch following Fortinet upgrade procedures. 4. Restart FortiMail services. 5. Verify version update.
🔧 Temporary Workarounds
Input Validation Filtering
allImplement input validation to filter CRLF sequences in user-supplied URLs
Not applicable - configuration-based workaround
User Awareness Training
allTrain users to avoid clicking suspicious links, especially in email contexts
🧯 If You Can't Patch
- Implement web application firewall rules to detect and block CRLF injection attempts
- Restrict access to FortiMail web interface to trusted networks only
🔍 How to Verify
Check if Vulnerable:
Check FortiMail version via web interface: System > Dashboard > System InformationCheck Version:
show system status (CLI) or check web interface dashboardVerify Fix Applied:
Verify version is 7.6.4+, 7.4.6+, or later patched version📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP header patterns in web logs
- Multiple requests with encoded CRLF sequences
Network Indicators:
- HTTP requests containing %0D%0A sequences in URLs
- Abnormal header responses from FortiMail
SIEM Query:
source="fortimail" AND (url="*%0D%0A*" OR header="*\r\n*")