CVE-2025-41693

4.3 MEDIUM

Denial of Service

📋 TL;DR

A low-privileged remote attacker can exploit SSH functionality to execute commands after authentication, causing resource exhaustion that degrades management performance. This affects systems with vulnerable SSH configurations where attackers have valid credentials. Switching functionality remains operational despite the performance impact.

💻 Affected Systems

Products:

Unknown specific products - refer to vendor advisory

Versions: Unknown - refer to vendor advisory

Operating Systems: Unknown - likely affects multiple OS with vulnerable SSH implementations

Default Config Vulnerable: ⚠️ Yes

Notes: Requires SSH access with low-privilege credentials; management functions specifically affected while switching functionality remains operational

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Sustained exploitation could exhaust system resources, leading to denial of service for management functions and potential system instability.

🟠

Likely Case

Attackers with low-privilege access create persistent resource-consuming processes, degrading management interface performance without complete system failure.

🟢

If Mitigated

With proper access controls and monitoring, impact is limited to minor performance fluctuations that don't affect core functionality.

🌐 Internet-Facing: MEDIUM

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: LOW

Requires valid low-privilege SSH credentials; exploitation involves command execution through SSH session

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Unknown

Vendor Advisory: https://certvde.com/de/advisories/VDE-2025-071

Restart Required: No

Instructions:

1. Monitor vendor advisory for patch availability
2. Apply vendor-recommended updates when released
3. Test in non-production environment first

🔧 Temporary Workarounds

Restrict SSH Access

all

Limit SSH access to trusted IP addresses and users only

# In sshd_config: AllowUsers trusted_user@trusted_ip
# In sshd_config: AllowGroups trusted_group

Implement Session Limits

linux

Configure SSH session timeouts and process limits

# In sshd_config: ClientAliveInterval 300
# In sshd_config: ClientAliveCountMax 2
# Set ulimits for SSH users

🧯 If You Can't Patch

Implement strict SSH access controls and multi-factor authentication
Deploy resource monitoring and alerting for abnormal process behavior

🔍 How to Verify

Check if Vulnerable:

Check SSH configuration and review if low-privilege users can execute commands that persist beyond session termination

Check Version:

ssh -V

Verify Fix Applied:

Test with low-privilege credentials to verify command execution doesn't cause resource exhaustion

📡 Detection & Monitoring

Log Indicators:

Unusual SSH session duration
Multiple persistent processes from same low-privilege user
Resource exhaustion alerts

Network Indicators:

Sustained SSH connections from single source
Abnormal command execution patterns over SSH

SIEM Query:

source="sshd" (session_duration>3600 OR process_count>10) | stats count by user, src_ip

📊 Metadata

CVE ID: CVE-2025-41693

CVSS v3 Score: 4.3 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CWE: CWE-770

EPSS Score: 0.26% exploit probability (49.6th percentile)

Published: December 9, 2025

Last Updated: December 19, 2025

🔗 References

https://certvde.com/de/advisories/VDE-2025-071 Third Party Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

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