CVE-2025-14055: Silicon Labs Secure NCP Buffer Overflow

CVE-2025-14055 Overview

An integer underflow vulnerability has been identified in the Silicon Labs Secure NCP (Network Co-Processor) host implementation. This flaw allows an attacker with physical access to trigger a buffer overread by sending a specially crafted packet to the affected device. The vulnerability stems from improper handling of integer arithmetic operations during packet processing, which can result in reading memory beyond intended buffer boundaries.

Critical Impact

Physical access exploitation could lead to information disclosure or device instability in Silicon Labs Secure NCP implementations.

Affected Products

• Silicon Labs Secure NCP host implementation

Discovery Timeline

• 2026-02-20 - CVE-2025-14055 published to NVD
• 2026-02-20 - Last updated in NVD database

Technical Details for CVE-2025-14055

Vulnerability Analysis

This vulnerability is classified as an Out-of-Bounds Read (CWE-125), resulting from an integer underflow condition in the Silicon Labs Secure NCP host implementation. The flaw occurs during packet processing, where arithmetic operations on packet length or offset values can underflow, producing unexpectedly large values that bypass buffer boundary checks.

When an attacker sends a specially crafted packet with malicious length fields, the integer underflow causes the application to calculate an incorrect buffer read length. This leads to accessing memory beyond the allocated buffer, potentially exposing sensitive data stored in adjacent memory regions or causing application instability.

The vulnerability requires physical access to exploit, limiting the attack surface to scenarios where an adversary has direct access to the device or communication interface. While this reduces the likelihood of remote exploitation, embedded IoT and industrial control environments where Silicon Labs NCP implementations are deployed may still face significant risk from insider threats or compromised physical security.

Root Cause

The root cause lies in insufficient validation of integer arithmetic operations during packet processing in the Secure NCP host implementation. When processing packet length or offset fields, the code fails to properly check for underflow conditions before performing subtraction operations. This allows specially crafted packets with manipulated values to trigger an underflow, resulting in an unexpectedly large computed value that bypasses subsequent boundary checks.

Attack Vector

The attack requires physical access to the target device running the Silicon Labs Secure NCP host implementation. An attacker must be able to send specially crafted packets directly to the NCP interface. The exploitation process involves:

1. Gaining physical access to the target device or its communication interface
2. Crafting a malicious packet with manipulated length or offset fields designed to trigger the integer underflow
3. Sending the packet to the Secure NCP host implementation
4. The integer underflow causes incorrect buffer boundary calculations, leading to an out-of-bounds read operation

The vulnerability does not require authentication or user interaction to exploit once physical access is obtained. For detailed technical information, refer to the Silicon Labs Community Post.

Detection Methods for CVE-2025-14055

Indicators of Compromise

• Unexpected device crashes or restarts in Silicon Labs NCP implementations
• Memory access violations or segmentation faults in NCP host processes
• Anomalous packet patterns with unusual length fields on NCP communication interfaces

Detection Strategies

• Monitor system logs for memory access violations or buffer overread errors in NCP-related processes
• Implement packet inspection to detect malformed packets with suspicious length or offset values
• Deploy endpoint detection solutions capable of identifying memory corruption attempts on embedded devices

Monitoring Recommendations

• Enable detailed logging on Silicon Labs NCP host implementations to capture packet processing events
• Implement physical access monitoring and alerting for sensitive embedded device deployments
• Establish baseline behavior for NCP communication patterns to identify anomalous traffic

How to Mitigate CVE-2025-14055

Immediate Actions Required

• Review physical security controls for devices running Silicon Labs Secure NCP implementations
• Restrict physical access to NCP interfaces to authorized personnel only
• Monitor for vendor-released patches addressing CVE-2025-14055
• Evaluate deployment environments for exposure to physical access threats

Patch Information

Consult the Silicon Labs Community Post for official patch information and firmware updates addressing this vulnerability. Organizations should apply vendor-provided patches as soon as they become available.

Workarounds

• Implement physical security controls to restrict access to affected devices
• Deploy network segmentation to isolate NCP-enabled devices from untrusted physical access points
• Consider disabling or removing affected NCP functionality if not required for operations
• Implement monitoring solutions to detect unauthorized physical access attempts