CVE-2025-1674: Zephyr Buffer Overflow Vulnerability

CVE-2025-1674 Overview

CVE-2025-1674 is an out-of-bounds read vulnerability affecting the Zephyr Real-Time Operating System (RTOS). The vulnerability stems from a lack of input validation in the packet processing functionality, allowing attackers to trigger out-of-bounds memory reads through malicious or malformed network packets. This vulnerability poses significant risk to IoT devices and embedded systems running Zephyr, potentially enabling information disclosure and denial of service attacks.

Critical Impact

Remote attackers can exploit this vulnerability without authentication to read sensitive memory contents or crash affected Zephyr-based devices, potentially disrupting critical IoT infrastructure.

Affected Products

• Zephyrproject Zephyr RTOS (all versions prior to the security patch)
• IoT devices and embedded systems built on the Zephyr platform
• Connected devices using Zephyr's network stack for packet processing

Discovery Timeline

• 2025-02-25 - CVE-2025-1674 published to NVD
• 2025-02-28 - Last updated in NVD database

Technical Details for CVE-2025-1674

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory safety issue that occurs when the application reads data past the allocated buffer boundaries. In the context of Zephyr RTOS, the network stack fails to properly validate the size and bounds of incoming packet data before processing, allowing crafted packets to trigger reads beyond the intended memory region.

The network attack vector enables remote exploitation without requiring any authentication or user interaction. An attacker can send specially crafted packets to a vulnerable Zephyr device, causing the application to read memory outside the intended buffer. This can result in exposure of sensitive information stored in adjacent memory regions or cause the device to crash due to accessing invalid memory addresses.

Root Cause

The root cause of CVE-2025-1674 is insufficient input validation in the Zephyr RTOS network packet processing code. When handling incoming network packets, the code fails to verify that packet length fields and buffer boundaries are within expected ranges before performing read operations. This oversight allows malformed packets with incorrect or oversized length values to bypass boundary checks, leading to out-of-bounds memory access.

Attack Vector

The vulnerability can be exploited remotely over the network without requiring any prior authentication or user interaction. An attacker with network access to a vulnerable Zephyr device can craft malicious packets containing invalid length fields or manipulated header data. When the Zephyr network stack processes these packets, it attempts to read beyond the allocated buffer boundaries.

The attack flow typically involves:

1. Identifying a target device running vulnerable Zephyr firmware
2. Crafting network packets with malformed length fields or invalid boundaries
3. Sending the malicious packets to the target device
4. The device's network stack processes the packet without proper validation
5. Out-of-bounds read occurs, potentially leaking memory contents or causing a crash

For detailed technical information about the vulnerability mechanism and affected code paths, refer to the GitHub Security Advisory GHSA-x975-8pgf-qh66.

Detection Methods for CVE-2025-1674

Indicators of Compromise

• Unexpected device crashes or reboots, particularly during network activity
• Abnormal network traffic patterns with malformed or oversized packets targeting Zephyr devices
• Memory corruption indicators in device logs or crash dumps
• Unusual memory access patterns in embedded system diagnostics

Detection Strategies

• Deploy network intrusion detection systems (IDS) to identify malformed packets targeting IoT devices
• Monitor Zephyr device logs for segmentation faults, memory access violations, or unexpected terminations
• Implement network traffic analysis to detect packets with invalid length fields or boundary violations
• Use firmware integrity monitoring to detect potential exploitation attempts

Monitoring Recommendations

• Enable verbose logging on Zephyr devices to capture packet processing errors and memory access violations
• Configure network monitoring to alert on traffic anomalies targeting embedded device ports
• Implement centralized logging for IoT device fleets to identify patterns of exploitation attempts
• Set up automated alerts for device crashes or unexpected reboots in Zephyr-based infrastructure

How to Mitigate CVE-2025-1674

Immediate Actions Required

• Inventory all devices running Zephyr RTOS to identify vulnerable systems
• Apply the latest Zephyr security patches as referenced in the vendor advisory
• Implement network segmentation to isolate vulnerable IoT devices from untrusted networks
• Deploy network-level filtering to block malformed packets before they reach vulnerable devices

Patch Information

The Zephyr Project has released security patches to address this vulnerability. Affected users should review the GitHub Security Advisory GHSA-x975-8pgf-qh66 for specific patch information and upgrade instructions. Organizations should prioritize updating to the patched version of Zephyr RTOS and rebuilding affected firmware.

Workarounds

• Implement network firewalls or access control lists to restrict access to vulnerable Zephyr devices
• Deploy intrusion prevention systems (IPS) capable of filtering malformed network packets
• Isolate affected devices on dedicated network segments with strict ingress filtering
• Consider disabling unused network services on Zephyr devices until patches can be applied

# Example: Network isolation for vulnerable Zephyr devices
# Add firewall rules to restrict access to IoT device network segment
iptables -A INPUT -s <trusted_network> -d <zephyr_device_network> -j ACCEPT
iptables -A INPUT -d <zephyr_device_network> -j DROP