CVE-2025-62875
📋 TL;DR
An Improper Check for Unusual or Exceptional Conditions vulnerability in OpenSMTPD allows local users to crash the service through a denial-of-service attack. This affects openSUSE Tumbleweed systems running vulnerable versions of OpenSMTPD. The vulnerability requires local access to the system.
💻 Affected Systems
- OpenSMTPD
📦 What is this software?
Opensmtpd by Opensmtpd
Tumbleweed by Opensuse
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of email service on affected systems, potentially disrupting mail flow and dependent services.
Likely Case
Local users can crash OpenSMTPD, causing temporary email service disruption until the service is restarted.
If Mitigated
With proper access controls limiting local user privileges, the impact is reduced to authorized users only.
🎯 Exploit Status
Reproducer code is publicly available in the security advisory. Exploitation requires local user access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.8.0p0-1.1 or later
Vendor Advisory: https://security.opensuse.org/2025/10/31/opensmtpd-local-DoS.html
Restart Required: Yes
Instructions:
1. Update OpenSMTPD package using your package manager. 2. For openSUSE Tumbleweed: 'sudo zypper update opensmtpd'. 3. Restart OpenSMTPD service: 'sudo systemctl restart smtpd'.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit which users have local shell access to systems running OpenSMTPD
Implement service monitoring
linuxSet up monitoring to automatically restart OpenSMTPD if it crashes
sudo systemctl enable smtpd
sudo systemctl start smtpd
🧯 If You Can't Patch
- Implement strict access controls to limit which users have local system access
- Monitor OpenSMTPD service status and set up automated restart procedures
🔍 How to Verify
Check if Vulnerable:
Check OpenSMTPD version: 'opensmtpd -V' or 'rpm -q opensmtpd' and compare against vulnerable versionsCheck Version:
opensmtpd -V 2>&1 | head -1 || rpm -q opensmtpdVerify Fix Applied:
Verify installed version is 7.8.0p0-1.1 or later: 'rpm -q opensmtpd'📡 Detection & Monitoring
Log Indicators:
- OpenSMTPD crash logs
- Unexpected service restarts in system logs
- Increased restart frequency in smtpd logs
Network Indicators:
- SMTP service becoming unavailable
- Failed email delivery attempts
SIEM Query:
source="systemd" AND "smtpd" AND ("failed" OR "crash" OR "restart")