CVE-2025-41697

6.8 MEDIUM

📋 TL;DR

This vulnerability allows attackers to exploit an undocumented UART port on printed circuit boards as a side-channel attack vector to gain root access, typically after obtaining credentials through CVE-2025-41692. It affects embedded systems and IoT devices with exposed UART interfaces. Physical access or proximity to the hardware is required for exploitation.

💻 Affected Systems

Products:

Embedded systems with exposed UART ports
IoT devices with accessible PCB interfaces

Versions: All versions with exposed UART interfaces

Operating Systems: Embedded Linux, Real-time operating systems, Custom firmware

Default Config Vulnerable: ⚠️ Yes

Notes: Vulnerability requires physical access to hardware and exploitation of CVE-2025-41692 credentials first. Affects devices with insufficient physical security around PCB interfaces.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise with root access, enabling persistent backdoors, data exfiltration, and device repurposing for botnets or further attacks.

🟠

Likely Case

Local privilege escalation to root on devices where attackers have physical access, allowing modification of firmware and system configuration.

🟢

If Mitigated

Limited impact with proper physical security controls preventing unauthorized hardware access.

🌐 Internet-Facing: LOW - Requires physical access to hardware interfaces, not remotely exploitable over networks.

🏢 Internal Only: MEDIUM - Physical access within facilities could allow exploitation, but requires specific hardware knowledge and tools.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: LIKELY

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires physical hardware access, UART interface identification, and serial communication tools. Typically follows credential compromise from CVE-2025-41692.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Not applicable - hardware design issue

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

Restart Required: No

Instructions:

1. Consult manufacturer for hardware redesign recommendations
2. Apply physical security measures to prevent UART access
3. Implement firmware updates to disable or secure UART interfaces

🔧 Temporary Workarounds

Physical UART Port Disablement

all

Physically disable or obscure UART ports on PCBs to prevent access

Firmware UART Disable

linux

Modify firmware to disable UART functionality in production devices

# Requires firmware modification - consult manufacturer

🧯 If You Can't Patch

Implement strict physical access controls to prevent unauthorized hardware access
Deploy tamper-evident seals and monitoring around device enclosures

🔍 How to Verify

Check if Vulnerable:

Inspect physical device for exposed UART pins on PCB. Check if serial console access is possible with tools like minicom or screen.

Check Version:

Not applicable - hardware vulnerability

Verify Fix Applied:

Verify UART ports are physically inaccessible or disabled. Test serial connection attempts fail.

📡 Detection & Monitoring

Log Indicators:

Serial console login attempts
Unexpected root access from local terminals
Hardware tamper detection alerts

Network Indicators:

Not network exploitable - physical access required

SIEM Query:

source="serial" OR source="console" AND (event="login" OR event="root")

📊 Metadata

CVE ID: CVE-2025-41697

CVSS v3 Score: 6.8 (MEDIUM)

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

CWE: CWE-1299

EPSS Score: 0.03% exploit probability (6.6th 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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