CVE-2025-65409
📋 TL;DR
A divide-by-zero vulnerability in GNU Recutils v1.9 encryption/decryption routines allows attackers to cause a Denial of Service (DoS) by providing an empty password value. This affects systems using Recutils for data encryption/decryption operations. The vulnerability can crash the application, disrupting data processing functionality.
💻 Affected Systems
- GNU Recutils
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete application crash leading to service unavailability, potential data corruption if encryption/decryption operations are interrupted during critical processes.
Likely Case
Application crash when processing encrypted data with empty passwords, requiring manual restart and causing temporary service disruption.
If Mitigated
Minimal impact with proper input validation and error handling in place; application gracefully handles malformed input without crashing.
🎯 Exploit Status
Exploitation requires ability to provide input to encryption/decryption routines; trivial to trigger with empty password input.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check latest version from GNU repositories (likely v1.9.1 or later)
Vendor Advisory: https://lists.gnu.org/archive/html/bug-recutils/2025-10/msg00004.html
Restart Required: Yes
Instructions:
1. Download latest Recutils from http://ftp.gnu.org/gnu/recutils/ 2. Compile and install following GNU instructions 3. Restart any services using Recutils
🔧 Temporary Workarounds
Input Validation Wrapper
linuxImplement pre-processing script to validate password inputs before passing to Recutils
#!/bin/bash
if [ -z "$PASSWORD" ]; then
echo "Error: Password cannot be empty"
exit 1
fi
# Continue with recutils command
Disable Encryption Features
allTemporarily disable encryption/decryption functionality if not required
# Modify application configuration to avoid using recutils encryption features
🧯 If You Can't Patch
- Implement strict input validation to reject empty passwords before reaching Recutils
- Monitor application logs for crash events and implement automatic restart mechanisms
🔍 How to Verify
Check if Vulnerable:
Check Recutils version: recutils --version | grep '1.9' and test with empty password input to encryption functionCheck Version:
recutils --versionVerify Fix Applied:
Test with empty password input after patch; application should handle gracefully without crashing📡 Detection & Monitoring
Log Indicators:
- Application crash logs
- Segmentation fault errors
- Divide by zero exceptions in system logs
Network Indicators:
- Sudden service unavailability
- Failed encryption/decryption API calls
SIEM Query:
source="application.logs" AND ("segmentation fault" OR "divide by zero" OR "recutils crash")🔗 References
- http://ftp.gnu.org/gnu/recutils/
- https://github.com/MAXEUR5/Vulnerability_Disclosures/blob/main/2025/CVE-2025-65409.md
- https://lists.gnu.org/archive/html/bug-recutils/2025-10/msg00004.html
- https://www.gnu.org/software/recutils/
- https://github.com/MAXEUR5/Vulnerability_Disclosures/blob/main/2025/CVE-2025-65409.md
